Open Geospatial Consortium Inc.
Date: 2006-03-15
Reference number of this document: OGC® 06-042
Version: 1.3.0®

Category: OpenGIS Implementation Specification
Editor: Jeff de la Beaujardiere

OpenGIS® Web Map Server Implementation Specification

Copyright © 2006 Open Geospatial Consortium, Inc. All Rights Reserved.
To obtain additional rights of use, visit http://www.opengeospatial.org/legal/.

®

Document type:
OpenGIS Implementation Specification
Document subtype: Not Applicable
Document stage:
Final
Document language: English

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OGC 06-042

Contents

Page

Foreword ............................................................................................................................................................iv
Introduction.........................................................................................................................................................v
1

Scope ......................................................................................................................................................6

2
2.1
2.2
2.3

Conformance .........................................................................................................................................6
Conformance classes and requirements ............................................................................................6
Basic WMS .............................................................................................................................................6
Queryable WMS .....................................................................................................................................63

Normative references............................................................................................................................64

Terms and definitions ...........................................................................................................................7

5

Abbreviated terms .................................................................................................................................8

6
6.1
6.2
6.3
6.4
6.5
6.6
6.7
6.8
6.9
6.10
6.11

Basic service elements .........................................................................................................................9Introduction............................................................................................................................................9
Version numbering and negotiation..................................................................................................10
General HTTP request rules ...............................................................................................................11
General HTTP response rules ............................................................................................................13
Numeric and Boolean values .............................................................................................................13
Output formats.....................................................................................................................................14
Coordinate systems ............................................................................................................................14
Request parameter rules ....................................................................................................................19
Common request parameters ............................................................................................................19
Service result .......................................................................................................................................20
Service exceptions ..............................................................................................................................20

7
7.1
7.2
7.3
7.4

Web Map Service operations .............................................................................................................21
Introduction..........................................................................................................................................21
GetCapabilities (mandatory) ..............................................................................................................21
GetMap (mandatory)............................................................................................................................32
GetFeatureInfo (optional)....................................................................................................................38

Annex A (normative) Conformance tests .......................................................................................................41
Annex B (normative) CRS Definitions ............................................................................................................44
Annex C (normative) Handling multi-dimensional data................................................................................51
Annex D (normative) Web Map Service profile of ISO 8601 .........................................................................57
Annex E (normative) XML Schemas ...............................................................................................................59
Annex F (normative) UML model.....................................................................................................................72
Annex G (informative) Web Mapping Examples ............................................................................................77
Annex H (informative) XML examples.............................................................................................................80
Bibliography......................................................................................................................................................85

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Foreword
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights.
OGC shall not be held responsible for identifying any or all such patent rights.
This version supercedes all previous versions of OpenGIS® Web Map Service Implementation Specification,
including OGC 04-024, 01-068r3, 01-047r2, 01-109r1 and OGC 00-028.

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Introduction
A Web Map Service (WMS) produces maps of spatially referenced data dynamically from geographic information.
This International Standard defines a “map” to be a portrayal of geographic information as a digital image file
suitable for display on a computer screen. A map is not the data itself. WMS-produced maps are generally
rendered in a pictorial format such as PNG, GIF or JPEG, or occasionally as vector-based graphical elements in
Scalable Vector Graphics (SVG) or Web Computer Graphics Metafile (WebCGM) formats.
This International Standard defines three operations: one returns service-level metadata; another returns a map
whose geographic and dimensional parameters are well-defined; and an optional third operation returns
information about particular features shown on a map. Web Map Service operations can be invoked using astandard web browser by submitting requests in the form of Uniform Resource Locators (URLs). The content ofsuch URLs depends on which operation is requested. In particular, when requesting a map the URL indicateswhat information is to be shown on the map, what portion of the Earth is to be mapped, the desired coordinate
reference system, and the output image width and height. When two or more maps are produced with the samegeographic parameters and output size, the results can be accurately overlaid to produce a composite map. The
use of image formats that support transparent backgrounds (e.g. GIF or PNG) allows underlying maps to bevisible. Furthermore, individual maps can be requested from different servers. The Web Map Service thus enables
the creation of a network of distributed map servers from which clients can build customized maps. Illustrative
examples of map request URLs and their resulting maps are shown in Annex G.
This International Standard applies to a Web Map Service instance that publishes its ability to produce maps
rather than its ability to access specific data holdings. A basic WMS classifies its geographic information holdings
into “Layers” and offers a finite number of predefined “Styles” in which to display those layers. This International
Standard supports only named Layers and Styles, and does not include a mechanism for user-defined
symbolization of feature data.
NOTE
The Open Geospatial Consortium (OGC) Styled Layer Descriptor (SLD) specification [6] defines a mechanism foruser-defined symbolization of feature data instead of named Layers and Styles. In brief, an SLD-enabled WMS retrieves
feature data from a Web Feature Service [7] and applies explicit styling information provided by the user in order to render amap.

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Geographic information — Web map server interface

1

Scope

This International Standard specifies the behaviour of a service that produces spatially referenced maps
dynamically from geographic information. It specifies operations to retrieve a description of the maps offered by aserver to retrieve a map, and to query a server about features displayed on a map. This International Standard isapplicable to pictorial renderings of maps in a graphical format; it is not applicable to retrieval of actual feature
data or coverage data values.

2

Conformance

2.1

Conformance classes and requirements

This International Standard defines two conformance classes, one for a basic WMS, and the other for a queryable
WMS. Each has two subclasses, one for clients and the other for servers.

2.2

Basic WMS

A basic WMS shall support the basic service elements (see Clause 6), the GetCapabilities operation (see 7.2),
and the GetMap operation (see 7.3). To conform to this International Standard, a basic WMS shall satisfy therequirements of A.1 of the Abstract Test Suite in Annex A.

2.3

Queryable WMS

A queryable WMS shall satisfy all the requirements for a basic WMS, and shall also support the GetFeatureInfo
operation (see 7.4). To conform to this International Standard, a queryable WMS shall satisfy all requirements of
the Abstract Test Suite in Annex A.

3

Normative references

The following referenced documents are indispensable for the application of this document. For dated references,
only the edition cited applies. For undated references, the latest edition of the referenced document (including any
amendments) applies.
ISO 8601:2004, Data elements and interchange formats — Information interchange — Representation of dates
and times
ISO 19111, Geographic information — Spatial referencing by coordinates
ISO 19115:2003, Geographic information — Metadata
EPSG (February 2003), European Petroleum Survey Group Geodesy Parameters, Lott, R., Ravanas, B., Cain, J.,
Simonson, G, and Nicolai, R., eds., available at <http://www.epsg.org/>

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IETF RFC 2045 (November 1996), Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet
Message Bodies, Freed, N. and Borenstein, N., eds., available at <http://www.ietf.org/rfc/rfc2045.txt>
IETF RFC 2396 (August 1998), Uniform Resource Identifiers (URI): Generic Syntax, Berners-Lee, T., Fielding, N.,
and Masinter, L., eds., available at <http://www.ietf.org/rfc/rfc2396.txt>
IETF RFC 2616 (June 1999), Hypertext Transfer Protocol – HTTP/1.1, Gettys, J., Mogul, J., Frystyk, H.,
Masinter, L., Leach, P., and Berners-Lee, T., eds., available at <http://www.ietf.org/rfc/rfc2616.txt>
UCUM, Unified Code for Units of Measure, Schadow, G. and McDonald, C.J. (eds.), version 1.5<http://aurora.regenstrief.org/UCUM/ucum.html>
XML 1.0, Extensible Markup Language (XML) 1.0, World Wide Web Consortium Recommendation, Bray, T.,
Paoli, J., Sperberg-McQueen, C.M., and Maler, E., eds., available at <http://www.w3.org/TR/>XML Schema, XML Schema Part 1: Structures, World Wide Web Consortium Recommendation, Thompson, H.S.,
Beech, D., Maloney, M., and Mendelsohn, N., eds., available at <http://www.w3.org/TR/>

4

Terms and definitions

For the purposes of this document, the following terms and definitions apply.
4.1
clientsoftware component that can invoke an operation from a server
4.2
coordinate reference systemcoordinate system that is related to the real world by a datum[ISO 19111]
4.3
coordinate system
set of mathematical rules for specifying how coordinates are to be assigned to points[ISO 19111]
4.4
geographic information
information concerning phenomena implicitly or explicitly associated with a location relative to the Earth[ISO 19101]
4.5interface
named set of operations that characterize the behaviour of an entity[ISO 19119]
4.6
layer
basic unit of geographic information that may be requested as a map from a server

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4.7
map
portrayal of geographic information as a digital image file suitable for display on a computer screen
4.8
operation
specification of a transformation or query that an object may be called to execute[ISO 19119]
4.9
portrayalpresentation of information to humans[ISO 19117]
4.10
requestinvocation of an operation by a client
4.11
response
result of an operation returned from a server to a client
4.12
servera particular instance of a service
4.13
servicedistinct part of the functionality that is provided by an entity through interfaces[ISO 14252]
4.14
service metadata
metadata describing the operations and geographic information available at a server

5Abbreviated terms

CDATA

XML Character Data

CRS

Coordinate Reference System

CS

Coordinate System

DCP

Distributed Computing Platform

DTD

Document Type Definition

EPSG

European Petroleum Survey GroupGIF

Graphics Interchange Format

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GIS

Geographic Information System

HTTP

Hypertext Transfer Protocol

IANA

Internet Assigned Numbers Authority

IERS

International Earth Rotation Service

IETF

Internet Engineering Task Force

ITRF

International Terrestrial Reference FrameITRSIERS Terrestrial Reference System

JPEG

Joint Photographic Experts GroupMIME

Multipurpose Internet Mail Extensions

NAD

North American Datum

OGC

Open GIS Consortium

PNG

Portable Network Graphics

RFC

Request for Comments

SVG

Scalable Vector Graphics

UCUM

Unified Code for Units of Measure

URL

Uniform Resource Locator

WebCGMWeb Computer Graphics Metafile

WCS

Web Coverage Service

WFS

Web Feature Service

WGS

World Geodetic System

WMS

Web Map Service

XML

Extensible Markup Language

6

Basic service elements

6.1

Introduction

This clause specifies aspects of Web Map Server behaviour that are independent of particular operations or arecommon to several operations.

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6.2

Version numbering and negotiation

6.2.1

Version number form and value

The Web Map Service (WMS) defines a protocol version number. The version number applies to the XML schema
and the request encodings defined in this International Standard. The version number contains three non-negative
integers, separated by decimal points, in the form “x.y.z”. The numbers “y” and “z” shall not exceed 99.
Implementations of this International Standard shall use the value “1.3.0” as the protocol version number.
6.2.2

Version number changes

The protocol version number shall be changed with each revision of this International Standard. The number shall
increase monotonically and shall comprise no more than three integers separated by decimal points, with the first
integer being the most significant. There may be gaps in the numerical sequence. Some numbers may denote
draft versions. Servers and their clients need not support all defined versions, but shall obey the negotiation rules
below.
6.2.3

Appearance in requests and in service metadata

The version number shall appear in at least two places: in the service metadata and in the parameter list of client
requests to a server. The version number used in a client’s request of a particular server shall be equal to aversion number which that server has declared it supports (except during negotiation, as described below). A
server may support several versions, whose values clients may discover according to the negotiation rules.
6.2.4

Version number negotiation

A WMS client may negotiate with a server to determine a mutually agreeable protocol version. Negotiation is
performed using the GetCapabilities operation (described in 7.2) according to the following rules.
All service metadata shall include a protocol version number and shall comply with the XML DTD or Schema
defined for that version. In response to a GetCapabilities request (for which the VERSION parameter is optional)
that does not specify a version number, the server shall respond with the highest version it supports. In response
to a GetCapabilities request containing a version number that the server implements, the server shall send thatversion. If the server does not support the requested version, the server shall respond with output that conforms
to a version it does support, as determined by the following rules:⎯ If a version unknown to the server and higher than the lowest supported version is requested, the server shallsend the highest version it supports that is less than the requested version.
⎯ If a version lower than any of those known to the server is requested, then the server shall send the lowest
version it supports.
⎯ If the client does not support the version sent by the server, it may either cease communicating with theserver or send a new request with a different version number that the client does support.
The process may be repeated until a mutually understood version is reached, or until the client determines that it
will not or cannot communicate with that particular server.
EXAMPLE 1
Server understands versions 1, 2, 4, 5 and 8. Client understands versions 1, 3, 4, 6, and 7. Client requests
version 7. Server responds with version 5. Client requests version 4. Server responds with version 4, which the client
understands, and the negotiation ends successfully.

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EXAMPLE 2
Server understands versions 4, 5 and 8. Client understands version 3. Client requests version 3. Server
responds with version 4. Client does not understand that version or any higher version, so negotiation fails and client ceases
communication with that server.

The VERSION parameter is mandatory in requests other than GetCapabilities.

6.3

General HTTP request rules

6.3.1

Introduction

This International Standard defines the implementation of the WMS on a distributed computing platform (DCP)
comprising Internet hosts that support the Hypertext Transfer Protocol (HTTP) (see IETF RFC 2616). Thus, theOnline Resource of each operation supported by a server is an HTTP Uniform Resource Locator (URL). The URL
may be different for each operation, or the same, at the discretion of the service provider. Each URL shall conformto the description in IETF RFC 2616 (section 3.2.2 “HTTP URL”) but is otherwise implementation-dependent; only
the query portion comprising the service request itself is defined by this International Standard.
HTTP supports two request methods: GET and POST. One or both of these methods may be offered by a server,
and the use of the Online Resource URL differs in each case. Support for the GET method is mandatory; support
for the POST method is optional.
6.3.2

Reserved characters in HTTP GET URLs

The URL specification (IETF RFC 2396) reserves particular characters as significant and requires that these beescaped when they might conflict with their defined usage. This International Standard explicitly reserves severalof those characters for use in the query portion of WMS requests. When the characters “?”, “&”, “=”, “,” and “+”
appear in one of the roles defined in Table 1, they shall appear literally in the URL. When those characters appear
elsewhere (for example, in the value of a parameter), they shall be encoded as defined in IETF RFC 2396.
The server shall be prepared to decode any character escaped in this manner, and to decode the “+” character asa space.

Table 1 — Reserved characters in WMS query string
Character

6.3.3

Reserved usage?

Separator indicating start of query string.

&

Separator between parameters in query string.

=

Separator between name and value of parameter.

,

Separator between individual values in list-oriented parameters (such as BBOX, LAYERS and STYLES
in the GetMap request).

+

Shorthand representation for a space character.

HTTP GETA WMS shall support the “GET” method of the HTTP protocol (IETF RFC 2616).
An Online Resource URL intended for HTTP GET requests is in fact only a URL prefix to which additionalparameters are appended in order to construct a valid Operation request. A URL prefix is defined in accordancewith IETF RFC 2396 as a string including, in order, the scheme (“http” or “https”), Internet Protocol hostname or

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numeric address, optional port number, path, mandatory question mark “?”, and optional string comprising one ormore server-specific parameters ending in an ampersand “&”. The prefix defines the network address to which
request messages are to be sent for a particular operation on a particular server. Each operation may have a
different prefix. Each prefix is entirely at the discretion of the service provider.
This International Standard defines how to construct a query part that is appended to the URL prefix in order toform a complete request message. Every WMS operation has several mandatory or optional request parameters.
Each parameter has a defined name. Each parameter may have one or more legal values, which are either
defined by this International Standard or are selected by the client based on service metadata. To formulate thequery part of the URL, a client shall append the mandatory request parameters, and any desired optionalparameters, as name/value pairs in the form “name=value&” (parameter name, equals sign, parameter value,ampersand). The “&” is a separator between name/value pairs, and is therefore optional after the last pair in therequest string.
When the HTTP GET method is used, the client-constructed query part is appended to the URL prefix defined by
the server, and the resulting complete URL is invoked as defined by HTTP (IETF RFC 2616).
Table 2 summarizes the components of an operation request URL when HTTP GET is used.

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Table 2 — Structure of WMS request using HTTP GET
URL component

Description

http://host[:port]/path[?{name[=value]&}]URL prefix of service operation. [ ] denotes 0 or 1 occurrence of an
optional part; {} denotes 0 or more occurrences.

name=value&

One or more standard request parameter name/value pairs as definedfor each operation by this International Standard.

6.3.4

HTTP POST

A WMS may support the “POST” method of the HTTP protocol (IETF RFC 2616).
An Online Resource URL intended for HTTP POST requests is a complete URL (not merely a prefix as in the
HTTP GET case) that is valid according to IETF RFC 2396 to which clients transmit request parameters in the
body of the POST message. A WMS shall not require additional parameters to be appended to the URL in order
to construct a valid target for the operation request. When POST is used, the request message is formulated as
an XML document.

6.4

General HTTP response rules

Upon receiving a valid request, the server shall send a response corresponding exactly to the request as detailedin Clause 7 of this International Standard, or send a service exception if unable to respond correctly. Only in thecase of Version Negotiation (see 6.2.4) may the server offer a differing result. Upon receiving an invalid request,
the server shall issue a service exception as described in 6.11.
A server may send an HTTP Redirect message (using HTTP response codes as defined in IETF RFC 2616) to an
absolute URL that is different from the valid request URL that was sent by the client. HTTP Redirect causes theclient to issue a new HTTP request for the new URL. Several redirects could in theory occur. Practically speaking,the redirect sequence ends when the server responds with a WMS response. The final response shall be a WMS
response that corresponds exactly to the original request (or a service exception).
Response objects shall be accompanied by the appropriate Multipurpose Internet Mail Extensions (MIME) type
(IETF RFC 2045) for that object. A list of MIME types in common use on the internet is maintained by the Internet
Assigned Numbers Authority (IANA) [2]. Allowable types for operation responses and service exceptions are
discussed below. The basic structure of a MIME type is a string of the form “type/subtype”. MIME allows additionalparameters in a string of the form “type/subtype; param1=value1; param2=value2”. A server may include
parameterized MIME types in its list of supported output formats. In addition to any parameterized variants, theserver should offer the basic unparameterized version of the format.
Response objects should be accompanied by other HTTP entity headers as appropriate and to the extent
possible. In particular, the Expires and Last-Modified headers provide important information for caching; ContentLength may be used by clients to know when data transmission is complete and to efficiently allocate space forresults, and Content-Encoding or Content-Transfer-Encoding may be necessary for proper interpretation of theresults.

6.5

Numeric and Boolean values

Integer numbers shall be represented in a manner consistent with the specification for integers in XML Schema
Datatypes ([8], section 3.3.13). This International Standard shall explicitly indicate where an integer value ismandatory.

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Real numbers shall be represented in a manner consistent with the specification for double-precision numbers in
XML Schema Datatypes ([8], section 3.2.5). This representation allows for integer, decimal and exponential
notations. A real value is allowed in all numeric fields defined by this International Standard unless the value is
explicitly restricted to integer.
Positive, negative and zero values are allowed unless explicitly restricted.
Boolean values shall be represented in a manner consistent with the specification for Boolean in XML Schema
Datatypes ([8], section 3.2.2). The values “0” and “false” are equivalent. The values “1” and “true” are equivalent.
Absence of an optional value is equivalent to logical false. This International Standard shall explicitly indicate
where a Boolean value is mandatory.

6.6

Output formats

The response to a Web Map Service request is always a computer file that is transferred over the Internet fromthe server to the client. The file may contain text, or the file may represent a map image. As stated in 6.4, the typeof the returned file shall be indicated by a MIME type string.
Text output formats are usually formatted as Extensible Markup Language (XML; MIME type text/xml). Text
formats are used to convey service metadata, descriptions of error conditions, or responses to queries for
information about features shown on a map.
Allowed map formats are either “picture” formats or “graphic element” formats. Picture formats constitute a
rectangular pixel array of fixed size. Picture formats include file types such as Graphics Interchange Format (GIF;
MIME type “image/gif”), Portable Network Graphics (PNG; MIME type “image/png”), Joint Photographics Expert
Group (JPEG; MIME type “image/jpeg”), all of which can be displayed by common Web browsers, and file types
such as Tagged Image File Format (TIFF: MIME type “image/tiff”) that may require additional software (beyond abasic Web browser) for display. Graphic element formats constitute a scale-independent description of thegraphic elements to be displayed (including points, lines, curves, text and images), such that the size of thedisplay may be modified while preserving the relative arrangement of the graphic elements. Graphic element
formats include Scalable Vector Graphics (SVG; MIME type “image/svg+xml”) or Web Computer Graphics
Metafile (WebCGM; MIME type “image/cgm;Version=4;ProfileId=WebCGM”) formats.
NOTE 1
SVG is expressed using XML, and could therefore be considered to be a text output format, but for the purposes ofthis International Standard SVG is considered to be a map format.
NOTE 2

WebCGM is a profile of ISO/IEC 8632.

A server may offer multiple map formats. The formats it offers are enumerated in <Format> elements in its service
metadata. Use of a specific format is not required by this International Standard. However, for maps that portray
vector features the server should offer at least one format that supports transparency in order that maps may beoverlaid without obscuring other maps below (see the discussion about transparency in 7.3.3.9). Also, for ease ofuse, the server should offer at least one format that can be displayed by common Web browsers without
additional software. Based on these considerations, the server should offer at least the PNG format.

6.7

Coordinate systems

6.7.1

Introduction

This International Standard uses two principal classes of Coordinate Systems: a Map CS applicable to the map
portrayal generated by the WMS, and a Layer CRS for a Bounding Box applied to the source data. During a
portrayal operation, a WMS converts or transforms geographic information from a Layer CRS into a Map CS. In
addition, a Layer may have an associated vertical, temporal or other coordinate system.

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6.7.2

Map CSA Map CS is a coordinate reference system for a map produced by a WMS. A WMS map is a rectangular grid of
pixels displayed on a computer screen (or a digital file that could be so displayed). The Map CS has a horizontal
axis denoted i, and a vertical axis denoted j. i and j shall have only nonnegative integer values. The origin (i,j) =(0,0) is the pixel in the upper left corner of the map; i increases to the right and j increases downward. The Map
CS is defined using ISO 19111 terminology in B.2. The Map CS is identified by the label “CRS:1”.
The usual orientation of the Map CS shall be such that the i axis is parallel to the East-to-West axis of the Layer
CRS and increases Eastward, and the j axis is parallel to the North-to-South axis of the Layer CRS and increases
Southward. This orientation will not be possible in some cases, as (for example) in an orthographic projection over
the South Pole. The convention to be followed is that, wherever possible, East shall be to the right edge and North
shall be toward the upper edge of the Map CS.
The WIDTH and HEIGHT parameters used in the GetMap request (see 7.3.3.8) and by inclusion in the
GetFeatureInfo request (7.4.3.3) correspond to i and j as follows:⎯ WIDTH denotes the size of the map image in pixels along the i axis (that is, WIDTH-1 is the maximum valueof i).
⎯ HEIGHT denotes the size of the map image in pixels along the j axis (that is, HEIGHT-1 is the maximum
value of j).
The I and J parameters used in the GetFeatureInfo request (see 7.4.3.7) denote integer values along the i and jaxes, respectively, of the Map CS.
6.7.3
6.7.3.1

Layer CRS
Introduction

A Layer CRS is a horizontal coordinate reference system for the geographic information that serves as the source
for a map. As discussed below, many Layer CRSs are possible. A Layer CRS appears in the following entities
relevant to the WMS:
⎯ the <BoundingBox> element in the service metadata (7.2.4.6.8);⎯ the CRS parameter in the GetMap request (7.3.3.5);⎯ the CRS parameter in the map request part of the GetFeatureInfo request (7.4.3.3).
A WMS must support at least one CRS, and maps from multiple servers may be overlaid only if all the selectedservers have at least one CRS in common. This International Standard does not mandate support for any
particular Layer CRS(s). Instead, it only defines how CRSs are identified and discusses several optional Layer
CRSs, in this clause and in Annex B. Map providers may support the CRSs that are most useful and appropriate
to their geographic locale or information community. To maximize interoperability among servers, providers
should also support geographic coordinates by geocentric coordinate systems such as “CRS:84” (see 6.7.3.2),“EPSG:4326” (see 6.7.3.3) or other ITRF-based systems.
Every Layer CRS has an identifier that is a character string. Two types of Layer CRS identifiers are permitted:“label” and “URL” identifiers:⎯ Label: The identifier includes a namespace prefix, a colon, a numeric or string code, and in some instances acomma followed by additional parameters. This International Standard defines three namespaces: CRS,EPSG and AUTO2, as discussed below.

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OGC 06-042⎯ URL: The identifier is a fully-qualified URL that references a publicly-accessible file containing a definition of
the CRS that is compliant with ISO 19111.
The Layer CRS has two axes, denoted x and y. The x axis is the first axis in the CRS definition, the y axis is thesecond axis. Depending on the particular CRS, the x axis may or may not be oriented West-to-East, and the y axis
may or may not be oriented South-to-North. The WMS portrayal operation shall account for axis order, origin anddirection in the Layer CRS when projecting geographic information from a Layer CRS to the Map CS.
Coordinates shall be listed in the order defined by the CRS and shall be mapped appropriately to the Map CS i
and j axes, swapping axis order as needed during the projection operation. Many projected coordinate reference
systems have an axis and coordinate order other than easting, northing. For example, the Uniform Coordinate
System used in Finland (EPSG:2393) orders northing before easting. EPSG geographic coordinate reference
systems follow ISO 6709 and always list latitude before longitude.
Most coordinate reference systems are orientated with one axis positive east (easting) and the other axis positive
north (northing). These map conveniently to the bounding box i and j axes, respectively. However, some CRSs
have coordinates incrementing in other directions. For example, the Hartebeesthoek94/Lo25 system used inSouth Africa (EPSG:2051) has axes with coordinates incrementing to the west and south. Tests for valid boundingbox areas shall recognise and account for the positive orientation of the CRS axes.
In a geographic CRS, latitude shall have values within the range [-90, 90] and longitude shall have values within
the range [-180, 180] degrees or equivalent if the CRS definition is in other units. See 7.3.5 regarding the
projection of Layer CRS that is a geographic CRS into the Map CS. When the CRS code specifies a geographic
2D coordinate reference system with axes in units other than degrees or in a degree representation other thandecimal degrees the representation shall be converted to decimal degrees.
NOTE
The use of geographic CRSs with axis order of longitude before latitude differs from historical convention. Users in
the international aviation and marine sectors may expect latitude to be before longitude, and a different coordinate display may
have safety implications, especially in an emergency response situation. Although this International Standard does not specify
human user interfaces, developers of user interfaces for WMSs are cautioned that all references to latitude and longitude, forexample user input of bounding box or readout of cursor coordinates, should show latitude before longitude.

6.7.3.2

CRS namespace for CRS

The “CRS” namespace prefix refers to coordinate reference systems that are defined in Annex B of thisInternational Standard. These definitions are in the form specified by ISO 19111. Geographic CRSs in the “CRS”
namespace are defined in Annex B for the WGS 84, NAD27 and NAD83 datums.
A “CRS” CRS label comprises the “CRS” prefix, the colon, and a numeric or string code.
EXAMPLE“CRS:84” refers to WGS 84 geographic longitude and latitude expressed in decimal degrees, with longitude
ranging from −180 degrees to +180 degrees and latitude from −90 degrees to +90 degrees.

6.7.3.3

EPSG namespace for CRS

The “EPSG” namespace prefix refers to the European Petroleum Survey Group geodetic dataset (EPSG), which
defines numeric identifiers (the EPSG “CRS code,” corresponding to the field “COORD_REF_SYS_CODE” in the
EPSG dataset) for many common coordinate reference systems. Defining geodetic, map projection andcoordinate reference system data is related to each CRS identifier.
An “EPSG” CRS label comprises the “EPSG” prefix, the colon, and a numeric code.
EXAMPLEEPSG:4326 refers to WGS 84 geographic latitude, then longitude. That is, in this CRS the x axis corresponds
to latitude, and the y axis to longitude.

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NOTE
EPSG geographic coordinate reference systems with axes of “degree – vendor-defined representation” are takenin this International Standard to be in decimal degrees.

6.7.3.4

AUTO2 namespace for CRS

The “AUTO2” namespace is used for “automatic” coordinate reference systems; that is, for a class of CRSs that
include a user-selected centre of projection. Several “AUTO2” CRSs are defined in Annex B.
A complete “AUTO2” CRS label comprises the “AUTO2” namespace prefix, a numeric CRS identifier from the
AUTO2 namespace, a number indicating what conversion factor to apply to convert between bounding box units
and AUTO2 CRS units, and values for the central longitude and latitude in degrees:
AUTO2:auto_crs_id,factor,lon0,lat0
The conversion factor shall be nonzero and positive. If factor=1, then the units of the BBOX values are the sameas those stated in the CRS definition. If factor is not 1, then factor is the ratio of BBOX units to CRS units. In a
GetMap request, the complete AUTO2 CRS is specified, including longitude, latitude and units. In service
metadata, the longitude, latitude and units variables are omitted because they are chosen by the client in arequest for an AUTO2 CRS.
EXAMPLE 1
A server indicates that it supports Auto Orthographic CRS by including the element“<CRS>AUTO2:42003</CRS>” in its service metadata. A client may issue a GetMap request for a map in this CRS, withbounding box in meters, centered at 100 degrees West longitude and 45 degrees North latitude, using the parameter“CRS=AUTO2:42003,1,-100,45”.
EXAMPLE 2
Same request as in example 1, but with conversion factor allowing bounding box in U.S. feet:"CRS=AUTO2:42003,0.3048006096012192,-100,45".

6.7.3.5

Geographic information with undefined CRS

A server may offer two-dimensional geographic information whose precise spatial reference is undefined. For
example, a hand-drawn historical map may represent an area of the Earth but not employ a modern coordinate
reference system, and an aerial photograph may not be precisely georeferenced. Such types of graphicalinformation shall be treated as an image, and the Map CS label “CRS:1” shall be used when declaring the Layer
CRS of such an object. Clients should not attempt to overlay a layer for which CRS=CRS:1 with another layer.
6.7.4

Bounding boxes

Bounding box values specify the portion of the Earth to be mapped through two pairs of coordinates in a specified
Layer CRS. The first pair specifies the minimum coordinate values in the Layer CRS, the second specifies
maximum coordinate values. Although for most CRSs with axes incrementing to the east and north this would be
the lower left and upper right corners of the area of interest, the minimum and maximum values might be at otherpoints in some instances. For example, when using geographic coordinates to describe an area over a pole, or
when the layer CRS axes increment in directions other than east and north. The order in which ordinates in eachpair are listed shall be as defined by the Layer CRS; x corresponds to the first axis in the Layer CRS and y to thesecond. This order may not coincide with the Map CS axis order i, j. The bounding box coordinate values shall bein the units defined for the Layer CRS.
NOTE
The use of two corner points to specify the map region is not the only possible method in theory. Other possibilities
include specifying a central point and a radius, or a central point and a zoom level or scale. Some services that use mapping(e.g. location-based services) may find a formalism based on the central point more appropriate. This International Standard is
not intended to preclude other service types from using other map region definitions internally or in client interactions. For mostcoordinate reference systems, it is a simple mathematical operation to transform between corner-point and central-point
methods. Thus, for example, user input of a central point and radius could be converted to a two-point bounding box whenrequesting a map from a WMS that implements this International Standard.

Bounding Box values appear in the following entities relevant to the WMS:

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OGC 06-042⎯ the <BoundingBox> element in the service metadata (7.2.4.6.8);⎯ the BBOX parameter in the GetMap request (7.3.3.6);⎯ the BBOX parameter in the map request part of the GetFeatureInfo request (7.4.3.3).
A Bounding Box shall not have zero area.
EXAMPLE 1
A <BoundingBox> metadata element for a Layer representing the entire Earth in the CRS:84 Layer CRS
would be written as<BoundingBox CRS="CRS:84" minx="-180" miny="-90" maxx="180" maxy="90">.
A BBOX parameter requesting a map of the entire Earth would be written in this CRS as
BBOX=-180,-90,180,90.
EXAMPLE 2
A <BoundingBox> representing the entire Earth in the EPSG:4326 Layer CRS would be written as<BoundingBox CRS="EPSG:4326" minx="-90" miny="-180" maxx="90" maxy="180">.
A BBOX parameter requesting a map of the entire Earth would be written in this CRS as
BBOX=-90,-180,90,180.

6.7.5

Vertical CRS

Some geographic information may be available at multiple elevations (for example, ozone concentrations at
different heights in the atmosphere). A WMS may announce available elevations in its service metadata, and the
GetMap operation includes an optional parameter for requesting a particular elevation. A single elevation or depth
value is a number whose units, and the direction in which ordinates increment, are declared through a onedimensional vertical CRS. Depending on the context, elevation values may appear as a single value, a list ofvalues, or an interval, as specified in Annex C.
A server may declare at most one vertical CRS for each layer. For the purposes of this International Standard, thehorizontal and vertical CRSs are treated as independent metadata elements and request parameters.
A request for a map at a specific elevation includes an elevation value but does not include the vertical CRS
identifier (the horizontal CRS, which is included along with the horizontal bounding box in the request parameters).
When providing elevation information, a server should declare a default value in service metadata, and a server
shall respond with the default value if one has been declared and the client request does not include a value.
Two types of Vertical CRS identifiers are permitted: “label” and “URL” identifiers:⎯ Label: The identifier includes a namespace prefix, a colon, and a numeric or string code. B.6 defines anoptional vertical CRS labelled “CRS:88” based on the North American Vertical Datum 1988. If the namespace
prefix is “EPSG”, then the vertical CRS is one of those defined in the European Petroleum Survey Group
database.
⎯ URL: The identifier is a fully-qualified Uniform Resource Locator that references a publicly-accessible filecontaining a definition of the CRS that is compliant with ISO 19111.
If the height is the vertical component of a 3-dimensional CRS, the Vertical CRS identifier shall be that of the 3dimensional CRS.
6.7.6

Temporal CS

Some geographic information may be available at multiple times (for example, an hourly weather map). A WMS
may announce available times in its service metadata, and the GetMap operation includes a parameter forrequesting a particular time. The format of a time string is specified in Annex D. Depending on the context, timevalues may appear as a single value, a list of values, or an interval, as specified in Annex C. When providing

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temporal information, a server should declare a default value in service metadata, and a server shall respond withthe default value if one has been declared and the client request does not include a value.
6.7.7

Other coordinate systems

Some geographic information may be available at other dimensions (for example, satellite images in different
wavelength bands). The dimensions other than the four space-time dimensions are referred to as “sample
dimensions”. A WMS may announce available sample dimensions in its service metadata, and the GetMap
operation includes a mechanism for requesting dimensional values. Each sample dimension has a Name and one
or more valid values. The declaration and use of sample dimensions are specified in C.3.3.

6.8

Request parameter rules

6.8.1

Parameter ordering and caseParameter names shall not be case sensitive, but parameter values shall be. In this International Standard,
parameter names are typically shown in uppercase for typographical clarity, not as a requirement.
Parameters in a request may be specified in any order.
When request parameters are duplicated with conflicting values, the response from the server may be undefined.
This International Standard does not mandate which of the duplicated values sent by the client are to be used by
the server.
A WMS shall be prepared to encounter additional request parameters that are not part of this International
Standard. In terms of producing results per this International Standard, a WMS shall not require such parameters.
6.8.2

Parameter lists

Parameters consisting of lists (for example, BBOX, LAYERS and STYLES in WMS GetMap) shall use the comma(“,”) as the separator between items in the list. Additional white space shall not be used to delimit list items. If a list
item value includes a space or comma, it shall be escaped using the URL encoding rules (see 6.3.2 andIETF RFC 2396).
In some lists, individual entries may be empty, and shall be represented by the empty string (“”). Thus, two
successive commas indicate an empty item, as does a leading comma or a trailing comma. An empty list (“”) shallbe interpreted either as a list containing no items or as a list containing a single empty item, depending on context.

6.9

Common request parameters

6.9.1

VERSION

The VERSION parameter specifies the protocol version number. The format of the version number, and version
negotiation, are described in 6.2.
6.9.2

REQUEST

The REQUEST parameter indicates which service operation is being invoked. The value shall be the name of oneof the operations offered by the server.
6.9.3

FORMATThe FORMAT parameter specifies the output format of the response to an operation.

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OGC 06-042

A WMS may offer only a subset of the formats known for that type of operation. The server shall advertise in its
service metadata those formats it does support and shall accept requests for any format it advertises. A server
may optionally offer a new format not previously offered by other instances, with the recognition that clients shallnot be required to accept or process an unknown format. If a request contains a format not offered by a particularserver, the server shall respond with the default format for that operation if one has been defined, or throw aservice exception (with code “InvalidFormat”) if no default has been defined.
A client may accept only a subset of the formats known for that type of operation. If a client and server do notsupport any mutually agreeable formats, the client may, at its discretion, cease communicating with that server, or
search for an intermediary service provider that performs format conversion, or allow the user to choose otherdisposition methods (e.g. saving to local storage or passing to a helper application).
Formats are expressed in both service metadata and in operation requests using MIME types. Each operation has
a distinct list of supported formats. Some formats may be offered by several operations, and are then duplicatedas needed in each list.
6.9.4

EXCEPTIONSThe EXCEPTIONS request parameter states the format in which to report errors (see 6.11).
6.9.5

Extended capabilities and operations

The Web Map Service allows for optional extended capabilities and operations. Extensions may be defined within
an information community when needed for additional functionality or specialization. A generic client shall not be
required or expected to make use of such extensions. Extended capabilities or operations shall be defined whennecessary by providing instances of the abstract <_ExtendedCapabilities> or <_ExtendedOperations> elements inthe service metadata schema in Annex E. Extended capabilities provide additional metadata about the service,
and may or may not enable optional new parameters to be included in operation requests. Extended operations
allow additional operations to be defined.
A server shall produce a valid response to the operations defined in this International Standard, even if
parameters used by extended capabilities are missing or malformed (i.e. the server shall supply a default value
for any extended capabilities it defines), or if parameters are supplied that are not known to the server.
Service providers shall choose extension names with care to avoid conflicting with standard metadata fields,parameters and operations.

6.10 Service result
The return value of a valid Service request shall correspond to the type requested in the FORMAT parameter. In
an HTTP environment, the Content-type header of the response shall be exactly the MIME type given in the valid
request.

6.11 Service exceptions
Upon receiving a request that is invalid according to this International Standard, the server shall issue a service
exception report. The service exception report is meant to describe to the client application or its human user thereason(s) that the request is invalid. The EXCEPTIONS parameter in a request indicates the format in which theclient wishes to be notified of service exceptions. The allowed service exception formats are defined for each
operation below.
Errors may arise in software modules other than those which implement the WMS, and may result in exception
messages other than those defined by this International Standard. For example, when an error condition occurs in
the local computing environment of the WMS server instance (e.g. out of memory or disk space), the server may

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be unable to process the WMS request and may issue an error message. Or, upon receiving a request that isinvalid according to the rules of the Distributed Computing Platform in use, the server may issue a service
exception of a type valid in that DCP (e.g. if the URL prefix is incorrect, an HTTP 404 status code
(IETF RFC 2616) may be sent).

7

Web Map Service operations

7.1

Introduction

The three operations defined for a WMS are GetCapabilities, GetMap, and GetFeatureInfo. GetFeatureInfo is
optional. This clause specifies the implementation and use of these WMS operations in the Hypertext Transfer
Protocol (HTTP) Distributed Computing Platform (DCP).

7.2

GetCapabilities (mandatory)

7.2.1

GeneralThe purpose of the mandatory GetCapabilities operation is to obtain service metadata, which is a machinereadable (and human-readable) description of the server’s information content and acceptable request parametervalues.
7.2.2

GetCapabilities request overview

The general form of a WMS request is defined in 6.3.3 and 6.3.4. When making the GetCapabilities request of a
WMS server, which may offer other service types as well, it is necessary to indicate that the client seeks
information about the Web Map Service in particular. Thus, the SERVICE parameter of the request shall have thevalue “WMS” as shown in Table 3.

Table 3 — The parameters of a GetCapabilities request URL
Request parameter

Mandatory/optional

Description

VERSION=version

O

Request version

SERVICE=WMS

M

Service type

REQUEST=GetCapabilities

M

Request name

FORMAT=MIME_type

O

Output format of service metadata

UPDATESEQUENCE=stringO

Sequence number or string for cache control

7.2.3
7.2.3.1

Request parameters
FORMAT

The optional FORMAT parameter states the desired format of the service metadata. Supported values for a
GetCapabilities request on a WMS server are listed in one or more <Request><GetCapabilities><Format>
elements of its service metadata. Every server shall support the default text/xml format defined in Annex A.
Support for other formats is optional. The entire MIME type string in <Format> is used as the value of the
FORMAT parameter. In an HTTP environment, the MIME type shall be set on the returned object using the HTTP

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OGC 06-042

Content-type entity header. If the request specifies a format not supported by the server, the server shall respondwith the default text/xml format.
7.2.3.2

VERSION

The optional VERSION parameter, and its use in version negotiation, is defined in 6.2.
7.2.3.3

SERVICEThe mandatory SERVICE parameter indicates which of the available service types at a particular server is being
invoked. When invoking GetCapabilities on a WMS that implements this version of the International Standard or alater one, the value “WMS” shall be used.
7.2.3.4

REQUEST

The nature of the mandatory REQUEST parameter is defined in 6.9.2. To invoke the GetCapabilities operation,
the value “GetCapabilities” shall be used.
7.2.3.5

UPDATESEQUENCE

The optional UPDATESEQUENCE parameter is for maintaining cache consistency. Its value can be either an
integer, or a string that represents a timestamp in ISO 8601:2004 format (see Annex D), or any other string. The
server may include an UpdateSequence value in its service metadata. If present, this value should be increased
when changes are made to the Capabilities (e.g. when new maps are added to the service). The client may
include this parameter in its GetCapabilities request. The response of the server based on the presence andrelative value of UpdateSequence in the client request and the server metadata shall be according to Table 4.
Table 4 — Use of UpdateSequence parameter
Client request
UpdateSequence value

Server metadata
UpdateSequence value

none

any

most recent service metadata

any

none

most recent service metadata

equal

equal

Exception: code=CurrentUpdateSequencelower

highermost recent service metadata

higherlower

Exception: code=InvalidUpdateSequence

7.2.4

Server response

GetCapabilities response

7.2.4.1

Introduction

When invoked on a WMS, the response to a GetCapabilities request shall be an XML document containing
service metadata formatted according to the XML Schema in E.1. The schema specifies the mandatory andoptional content of the service metadata and how the content is formatted. The XML document shall contain aroot element named WMS_Capabilities in the “http://www.opengis.net/wms” namespace. This element shallcontain an XML Schema instance schemaLocation attribute that binds the “http://www.opengis.net/wms”
namespace to the schema in E.1. The schema bound to the root attribute may be a copy of the schema in E.1
instead of the master copy at the URL stated in the annex provided none of the normative content of the schemais changed. The schema copy shall be located at a fully-qualified and accessible URL to permit XML validating
software to retrieve it. The response shall be valid according to XML Schema validation rules.

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A server may comply with other published or experimental protocol versions, in which case it shall support version
negotiation as described in 6.2.
7.2.4.2

Names and titles

A number of elements have both a <Name> and a <Title>. The Name is a text string used for machine-to-machinecommunication while the Title is for the benefit of humans. For example, a dataset might have the descriptive Title“Maximum Atmospheric Temperature” and be requested using the abbreviated Name “ATMAX”.
7.2.4.3

General service metadata

The first part of the service metadata is a <Service> element providing general metadata for the server as a whole.
It shall include a Name, Title, and Online Resource URL. Optional service metadata includes Abstract, Keyword
List, Contact Information, Fees, Access Constraints, and limits on the number of layers in a request or the output
size of maps.
The Service Name shall be “WMS” in the case of a WMS.
The Service Title is at the discretion of the provider, and should be brief yet descriptive enough to identify thisserver in a menu with other servers.
The Abstract element allows a descriptive narrative providing more information about the enclosing object.
The OnlineResource element within the Service element may be used to refer to the web site of the service
provider. There are other OnlineResource elements used for the URL prefix of each supported operation (seebelow).
A list of keywords or keyword phrases describing the server as a whole should be included to help catalogue
searching. Each keyword may be accompanied by a “vocabulary” attribute to indicate the defining authority forthat keyword. One “vocabulary” attribute value is defined by this International Standard: the value“ISO 19115:2003” refers to the metadata topic category codes defined in ISO 19115:2003, B.5.27; information
communities may define other “vocabulary” attribute values. No particular vocabulary is mandated by thisInternational Standard.
Contact Information should be included.
The optional <LayerLimit> element in the service metadata is a positive integer indicating the maximum number oflayers a client is permitted to include in a single GetMap request. If this element is absent, the server imposes nolimit.
The optional <MaxWidth> and <MaxHeight> elements in the service metadata are positive integers indicating the
maximum width and height values that a client is permitted to include in a single GetMap request. If either element
is absent the server imposes no limit on the corresponding parameter.
The optional elements <Fees> and <AccessConstraints> may be omitted if they do not apply to the server. If
either of those elements is present, the reserved word “none” (case-insensitive) shall be used if there are no feesor access constraints, as follows: <Fees>none</Fees>, <AccessConstraints>none</AccessConstraints>. When
constraints are imposed, no precise syntax has been defined for the text content of these elements, but client
applications may display the content for user information and action.
7.2.4.4

Capability metadata

The <Capability> element of the service metadata names the actual operations that are supported by the server,
the output formats offered for those operations, and the URL prefix for each operation. The XML schema includes

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OGC 06-042

placeholders for Distributed Computing Platforms other than HTTP, but currently only the HTTP platform isdefined.
7.2.4.5

Layers and styles

The most critical parts of the WMS service metadata are the Layers and Styles it defines. The geographic
information content offered for portrayal by a WMS server is organized into “layers”: metadata about the content is
subdivided into descriptions of each layer, and a request for a map names one or more layers. The terms “layer”
and “map” are defined in Clause 4; the relationship between them in the context of this International Standard isthat a map is the result of a request to portray information represented by a layer.
The Web Map Service provider decides what information to include, exclude or aggregate in each layer. However,each layer should be documented in accordance with ISO 19115 or FGDC-STD-001-1998 [1], and a link to that
metadata should be provided in the <MetadataURL> element defined below.
Each available map is advertised by a <Layer> element in the service metadata. Conceptually, each Layer is adistinct entity. However, as a means of classifying and organizing layers, and as a means of reducing the size ofthe service metadata, a single parent Layer may enclose any number of additional layers, which may behierarchically nested as desired. Some properties defined in a parent layer are inherited by the children it
encloses. These inherited properties may be either redefined or added to by the child. Subclause 7.2.4.8
summarizes whether or how each property is inherited.
A server shall include at least one <Layer> element for each map layer offered. If desired, layers may be repeatedin different categories (i.e. enclosed in more than one parent <Layer>) when relevant.
A list of keywords or keyword phrases describing each layer should be included to help catalogue searching.
Each keyword may be accompanied by a “vocabulary” attribute to indicate the defining authority for the keyword(see 7.2.4.3).
No controlled vocabulary of Layer and Style Names or Titles is defined by this International Standard, so they may
be chosen at the discretion of the service provider organization or information community.
7.2.4.6

Layer properties

7.2.4.6.1

Introduction

The <Layer> element can enclose child elements providing metadata about the Layer. The meanings of those
metadata elements are defined in this subclause. The values of some of these elements are inherited bysubsidiary layers as defined in 7.2.4.8.
Some of the metadata values, and additional metadata, may be available in ISO 19115 or
FGDC-STD-001-1998 [1] format as referenced via the <MetadataURL> element defined below. Table 5 shows therelationship between Layer Properties in this International Standard and ISO 19115 metadata elements. When
documenting layers with ISO 19115 metadata, service providers should ensure that fields listed as equivalent inTable 5 have identical values in the full 19115 and in the summary 19128 layer properties.

Table 5 — Relationship between ISO 19128 and ISO 19115 metadata fields
ISO 19128 layer property

ISO 19115 Metadata element

Relationship

Title

CI_Citation.title

equivalent

Abstract

MD_DataIdentification.abstractequivalent

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Keyword element in
KeywordList

MD_TopicCategoryCode

equivalent if “vocabulary” attribute of 19128<Keyword> element is “ISO 19115:2003”. Other
vocabularies are permitted by 19128.

EX_GeographicBoundingBox EX_GeographicBoundingBox

equivalentCRS

MD_CRS

Value of CRS in 19128 is a text string that identifies acoordinate reference system defined by anotherauthority. Value of MD_CRS in 19115 is a list of
projection, ellipsoid and datum identifiers.

BoundingBox

EX_BoundingPolygon

19128:BoundingBox is strictly a box (lower left andupper right corners in a specified CRS).
19115:EX_BoundingPolygon may be a polygonalboundary.

Attribution

CI_ResponsibleParty

Title element of 19128:Attribution is equivalent toorganisationName element of 19115:
CI_ResponsibleParty. Other elements of
19128:Attribution have no equivalent in 19115.

Identifier and AuthorityURL

CI_Citation.identifier

The value of 19128:Identifier is equivalent to19115:CI_Citation.identifier.code.
19128:AuthorityURL contains only the URL of theauthority for a namespace, and is equivalent to 19115:
CI_Citation.identifier.citation.citedResponsibleParty.
contactInfo.onlineResource. 19115 allows a fuller
description of the namespace authority.

DataURL

7.2.4.6.2

MD_metadata.dataSetURI

equivalent

Title

A <Title> is mandatory for all layers; it is a human-readable string for presentation in a menu. The Title is notinherited by child Layers.
7.2.4.6.3

Name

If, and only if, a layer has a <Name>, then it is a map layer that can be requested by using that Name in the
LAYERS parameter of a GetMap request. A Layer that contains a <Name> element is referred to as a “named
layer” in this International Standard. If the layer has a Title but no Name, then that layer is only a category title forall the layers nested within. A server that advertises a Layer containing a Name element shall be able to accept
that Name as the value of LAYERS argument in a GetMap request and return the corresponding map. A client
shall not attempt to request a layer that has a Title but no Name.
A server shall throw a service exception (code="LayerNotDefined") if an invalid layer is requested.
A containing category itself may include a Name by which a map portraying all of the nested layers can berequested at once. For example, a parent layer "Roads" may have children “Interstates” and “State Highways”
and allow the user to request either child individually or both together.
The Name is not inherited by child Layers.
7.2.4.6.4

Abstract and KeywordList

The optional <Abstract> and <KeywordList> elements are optional, but a server should provide them. Abstract isa narrative description of the map layer. KeywordList contains zero or more <Keyword> elements to aid in
catalogue searches. The Abstract and KeywordList elements are not inherited by child Layers.

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7.2.4.6.5

Style

Zero or more Styles may be advertised for a Layer or collection of layers using <Style> elements, each of whichshall have <Name> and <Title> elements. The style's Name is used in the Map request STYLES parameter. The
Title is a human-readable string. If only a single style is available, that style is known as the “default” style andneed not be advertised by the server.
A <Style> may contain several other elements. <Abstract> provides a narrative description while <LegendURL>
contains the location of an image of a map legend appropriate to the enclosing style. A <Format> element inLegendURL indicates the MIME type of the legend image, and the optional attributes width and height state
the size of the image in pixels. Servers should provide the width and height attributes if known at the time ofprocessing the GetCapabilities request. The legend image should clearly represent the symbols, lines and colours
used in the map portrayal. The legend image should not contain text that duplicates the Title of the layer, becausethat information is known to the client and may be shown to the user by other means.
Style declarations are inherited by child Layers. A child shall not redefine a Style with the same Name as one
inherited from a parent. A child may define a new Style with a new Name that is not available for the parent Layer.
7.2.4.6.6

EX_GeographicBoundingBox

Every named Layer shall have exactly one <EX_GeographicBoundingBox> element that is either stated explicitly
or inherited from a parent Layer. EX_GeographicBoundingBox states, via the elements westBoundLongitude,
eastBoundLongitude, southBoundLatitude, and northBoundLatitude, the minimum bounding rectangle in decimaldegrees of the area covered by the Layer. EX_GeographicBoundingBox shall be supplied regardless of what CRS
the map server may support, but it may be approximate if the data are not natively in geographic coordinates. The
purpose of EX_GeographicBoundingBox is to facilitate geographic searches without requiring coordinatetransformations by the search engine.
7.2.4.6.7

CRS

Every Layer is available in one or more layer coordinate reference systems. 6.7.3 discusses the Layer CRS. In
order to indicate which Layer CRSs are available, every named Layer shall have at least one <CRS> element thatis either stated explicitly or inherited from a parent Layer. The root <Layer> element shall include a sequence ofzero or more CRS elements listing all CRSs that are common to all subsidiary layers. A child layer may optionally
add to the list inherited from a parent layer. Any duplication shall be ignored by clients.
When a Layer is available in several coordinate reference systems, the list of available CRS values shall be
represented as a sequence of <CRS> elements, each of which contains only a single CRS name.
EXAMPLE

7.2.4.6.8<CRS>CRS:84</CRS> <CRS>EPSG:26718</CRS>.

BoundingBox

WMS service metadata shall declare one or more bounding boxes (as defined in 6.7.4) for each Layer.
A Bounding Box metadata element may either be stated explicitly or may be inherited from a parent Layer. In XML,the <BoundingBox> metadata element includes the following attributes:⎯ CRS indicates the Layer CRS that applies to this bounding box.
⎯ minx, miny, maxx, maxy indicate the limits of the bounding box using the axis units and order of thespecified CRS.
⎯ resx and resy (optional) indicate the spatial resolution of the data comprising the layer in those same units.
The <BoundingBox> metadata element has the following relationship to the BBOX request parameter defined in
7.3.3.6. The <BoundingBox> metadata element specifies the coordinate range for the layer as a whole. The

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BBOX request parameter, on the other hand, specifies which area is to be portrayed on the map. The BBOX area
may or may not overlap, contain, or be contained within the BoundingBox area.
A Layer may have multiple BoundingBox elements, but each one shall state a different CRS. A Layer inherits any
BoundingBox values defined by its parents. A BoundingBox inherited from the parent Layer for a particular CRS isreplaced by any declaration for the same CRS in the child Layer. A BoundingBox in the child for a new CRS notalready declared by the parent is added to the list of bounding boxes for the child Layer. A single Layer element
shall not contain more than one BoundingBox for the same CRS.
NOTE
There is no provision for describing disjoint bounding boxes. For example, consider a dataset which covers twoareas separated by some distance. The server cannot provide two separate bounding boxes in the same Layer using thesame CRS to separately describe those areas. To handle this type of situation, the server may either define a single larger
bounding box which encloses both areas, or may define two separate Layers that each have distinct Name and BoundingBox
values.

A Layer shall not provide a BoundingBox for a CRS it does not support. Conversely, a Layer may support CRSs
for which it does not provide a BoundingBox: a server that has the ability to transform data to different CRSs may
choose not to provide an explicit BoundingBox for every possible CRS available for each Layer. The server
should provide BoundingBox information for at least the native CRS of the Layer (that is, the CRS in which theLayer is stored in the server’s database).
The <EX_GeographicBoundingBox> element (see 7.2.4.6.6) is conceptually similar to a BoundingBox in which
the attribute CRS="CRS:84" is implicit. However, <EX_GeographicBoundingBox> shall not be used as a
substitute for <BoundingBox CRS="CRS:84">. If the server wishes to provide bounding box information in the
CRS:84 CRS, then a separate BoundingBox element explicitly naming CRS:84 shall be included in the service
metadata.
If the Layer CRS is "CRS:1" (Map CS; see B.2), then the BoundingBox units are pixels, the origin is at the upper
left, the first (x) axis increases to the right, and the second (y) axis increases toward the bottom.
7.2.4.6.9

Scale denominators

The <MinScaleDenominator> and <MaxScaleDenominator> elements define the range of scales for which it isappropriate to generate a map of a Layer. Because maps from a WMS may be viewed on arbitrary displays rather
than on paper, the values used are actually the scale denominators relative to a common display pixel size. The
intent of scale denominators is not that the translation between “actual” and “standard” scales always becompletely accurate. Rather, the intent is to reduce the amount of clutter or crowding of features portrayed on themap. The scale denominator values are guidelines for clients, not firm limits. Upon receiving a request for a mapthat is not within the scale denominator range, the server may return a blank map, or may return a portrayal of theLayer that is crowded with features or otherwise poorly suited for display; the server shall not respond with aservice exception.
For the purposes of this International Standard, the common pixel size is defined to be 0,28 mm × 0,28 mm.
Because arbitrary clients can request maps from a server, the true pixel size of the final rendering device isunknown to the server.
EXAMPLEA scale denominator value of “10000000” means a scale of 1:10 million. Scientific notation is also allowed, so
a more compact value of “10e6” could also be used for the scale denominator.

The MinScaleDenominator and MaxScaleDenominator elements, as their names suggest, define the range ofscale denominators of maps for which a Layer is appropriate. The minimum scale is inclusive and the maximum
scale is exclusive. So, for example, the following scale range:<MinScaleDenominator>1e3</MinScaleDenominator><MaxScaleDenominator>1e6</MaxScaleDenominator>

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corresponds to the logical condition:
scale_denom ≥ 103 AND scale_denom < 106
Both of the elements are optional. The absence of a MinScaleDenominator element means there is no minimumscale term to the condition or logically that the default value is zero. The absence of a MaxScaleDenominatorelement means that there is no maximum-scale term to the condition or logically that the default value is infinity.
So, the following scale constraint:<MinScaleDenominator>1e3</MinScaleDenominator>
corresponds to the logical condition:
scale_denom ≥ 103
There is a similar correspondence for a lone MaxScaleDenominator element. The absence of both scale elements
in Layer metadata means that there is no scale constraint and that the Layer is applicable to maps of all scales.
Because it is possible to integrate the output of multiple servers into a single displayed result, it is important thatdifferent servers have consistent behaviour with respect to processing scales, so that all of the independent
servers will select or deselect layers at the same scales. To ensure consistent behaviour, scales relative tocoordinate spaces must be handled consistently between map servers. For geographic coordinate systems, which
use angular units, the angular coverage of a map shall be converted to linear units for computation of scale byusing the circumference of the Earth at the equator and by assuming perfectly square linear units. For linear
coordinate systems, the size of the coordinate space should be used directly without compensating for distortionsin it with respect to the shape of the real Earth.
EXAMPLEA map to be displayed covers a 2-degree by 2-degree area in the WGS 84 geographic coordinates. The
linear size of this area for conversion to scales is:
2º × (6378137m × 2 × π) ÷ 360º = 222638,9816m.
Thus, the map extent would be approximately 222639m × 222639m linear distance for the purpose of calculating the scale. If
the image size for the map is 600×600 pixels, then the standard scale denominator for the map would be:
222638,9816m ÷ 600 pixels ÷ 0.00028m/pixel = 1325226,19.

Floating-point roundoff-error control should also be applied to these calculations, to ensure consistency between
systems. Because the scale denominators used in Layer metadata will often be “round” numbers, such as 250000,
if a calculation of the current scale results in a value of 249999,99999999, it should be considered to match
250000. A reasonable test for range matching of scale denominators would be defined as follows:scale ≥ (min_scale – epsilon) AND scale < (max_scale + epsilon)
where epsilon is defined as 1e-6.
Scale denominators are inherited by child Layers. A scale denominator declaration in the child replaces thedeclaration inherited from the parent.
7.2.4.6.10 Sample dimensions
Optional <Dimension> elements enclose metadata for multi-dimensional data. See the discussion of vertical,
temporal and other coordinate systems in 6.7.5 through 6.7.7, and the explanation of how dimensional axes andallowed values are declared and requested in Annex C.
Dimension declarations are inherited from parent Layers. Any new Dimension declaration in the child with thesame name attribute as one inherited from the parent replaces the value declared by the parent.

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7.2.4.6.11 MetadataURL
A server should use one or more <MetadataURL> elements to offer detailed, standardized metadata about thedata corresponding to a particular layer. The “type” attribute indicates the standard to which the metadata
complies. Two “type” attribute values are defined by this International Standard: the value “ISO 19115:2003”
refers to ISO 19115:2003; the value “FGDC:1998” refers to FGDC-STD-001-1998 [1]. An information community
may define meanings for other “type” attribute values. The enclosed <Format> element indicates the file format
MIME type of the metadata record.
MetadataURL elements are not inherited by child Layers.
7.2.4.6.12 Attribution
The optional <Attribution> element provides a way to identify the source of the geographic information used in a
Layer or collection of Layers. Attribution encloses several optional elements: <OnlineResource> states the data
provider’s URL; <Title> is a human-readable string naming the data provider; <LogoURL> is the URL of a logo
image. Client applications may choose to display one or more of these items. A <Format> element in LogoURL
indicates the MIME type of the logo image, and the attributes width and height state the size of the image inpixels.
The Attribution element is inherited by child layers. Any redefinition by a child replaces the inherited value.
7.2.4.6.13 Identifier and AuthorityURL
A server may use zero or more <Identifier> elements to list ID numbers or labels defined by a particular Authority.
The text content of the Identifier element is the ID value. The authority attribute of the Identifier element
corresponds to the name attribute of a separate <AuthorityURL> element. AuthorityURL encloses an<OnlineResource> element which states the URL of a document defining the meaning of the Identifier values.
NOTE
The semantics of how an authority defines the meaning of an identifier have not yet been precisely defined. The
Identifier and AuthorityURL elements are provided as a convenience for servers that wish to indicate the correspondence
between the WMS Layers they offer and a classification of those Layers defined by the organization that operates the server.
EXAMPLEThe Global Change Master Directory (http://gcmd.gsfc.nasa.gov/) defines a DIF_ID label for every datasetthat it has catalogued. A WMS that renders one of these datasets may associate a Layer with its DIF_ID in the following
manner:<AuthorityURL name="gcmd"><OnlineResource xlink:href="some_url" ... /></AuthorityURL><Identifier authority="gcmd">id_value</Identifier>

AuthorityURL is inherited by subsidiary layers. A child Layer shall not define an AuthorityURL with the same nameattribute as one inherited from a parent. The Identifier element is not inherited. A Layer shall not declare an
Identifier unless a corresponding AuthorityURL has been declared or inherited earlier in the service metadata.
7.2.4.6.14 FeatureListURL
A server may use a <FeatureListURL> element to point to a list of the features represented in a Layer.
FeatureListURL is not inherited by child layers. The enclosed Format element indicates the file format MIME typeof the feature list.
FeatureListURL is not inherited by child layers.
7.2.4.6.15 DataURL
A server may use DataURL to offer a link to the underlying data represented by a particular layer. The enclosed
Format element indicates the file format MIME type of the data file.

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DataURL is not inherited by child layers.
7.2.4.7

Layer attributes

7.2.4.7.1

Introduction

A <Layer> may have zero or more of the following XML attributes: queryable, cascaded, opaque, noSubsets,
fixedWidth, fixedHeight. All of these attributes are optional and default to 0. Each of these attributes can be
inherited or replaced by subsidiary layers. The meaning of each attribute is summarized in Table 6 and detailed in
the following subclauses.

Table 6 — Layer attributes
Attribute

Allowed values

Meaning (0 is default value)

queryable

0, false, 1, true0, false: layer is not queryable.
1, true: layer is queryable.

cascaded0, positive integer

0: layer has not been retransmitted by a Cascading Map Server.
n: layer has been retransmitted n times.

opaque0, false, 1, true0, false: map data represents vector features that probably do notcompletely fill space.
1, true: map data are mostly or completely opaque.

noSubsets

0, false, 1, true0, false: WMS can map a subset of the full bounding box.
1, true: WMS can only map the entire bounding box.

fixedWidth0, positive integer

0: WMS can produce map of arbitrary width.
nonzero: value is fixed map width that cannot be changed by the WMS.

fixedHeight0, positive integer

0: WMS can produce map of arbitrary height.
nonzero: value is fixed map height that cannot be changed by the WMS.

7.2.4.7.2

Queryable layers

The Boolean attribute queryable indicates whether the server supports the GetFeatureInfo operation on that
Layer. A server may support GetFeatureInfo on some of its layers, but need not support it on all layers. A server
shall issue a service exception (code="LayerNotQueryable") if GetFeatureInfo is requested on a Layer that is notqueryable.
7.2.4.7.3

Cascaded layers

A Layer is said to have been “cascaded” if it was obtained from an originating server and then included in theservice metadata of a different server. The second server may simply offer an additional access point for theLayer, or may add value by offering additional output formats or reprojection to other coordinate reference
systems.
If a WMS cascades the content of another WMS, then it shall increment by 1 the value of the cascaded attributefor the affected layers. If that attribute is missing from the originating server’s service metadata, then the
Cascading WMS shall insert the attribute and set it to 1.

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7.2.4.7.4

Opaque vs. transparent layers

If the optional Boolean attribute opaque is absent or false, then maps made from that Layer will generally havesignificant no-data areas that a client may display as transparent. Vector features such as points and lines are
considered not to be opaque in this context (even though at some scales and symbol sizes a collection of features
might fill the map area). A true value for opaque indicates that the Layer represents an area-filling coverage. For
example, a map that represents topography and bathymetry as regions of differing colours will have notransparent areas. The opaque declaration should be taken as a hint to the client to place such a Layer at thebottom of a stack of maps.
This attribute describes only the Layer’s data content, not the picture format of the map response. Whether or nota Layer is listed as opaque, a server shall still comply with 7.3.3.9 regarding the GetMap TRANSPARENT
parameter: that is, the server shall send an image with a transparent background if and only if the client requests
TRANSPARENT=TRUE and a picture FORMAT that supports transparency.
7.2.4.7.5

Subsettable and resizable layers

The Layer metadata may also include three optional attributes that indicate a map server that is less functional
than a normal WMS, because it is not able to extract a subset of a larger dataset or because it only serves mapsof a fixed size and cannot resize them. For example, a WMS that houses a collection of digitized images ofhistorical maps, or pre-computed browser images of satellite data, may not be able to subset or resize thoseimages. However, it can still respond to GetMap requests for complete maps in the original size.
Static image collections may not have a well-defined coordinate reference system, in which case the server shalldeclare CRS=CRS:1 as described in 6.7.2.
When set to a true value, noSubsets indicates that the server is not able to make a map of a geographic areaother than the layer's bounding box.
When present and nonzero, fixedWidth and fixedHeight indicate that the server is not able to produce a map of
the layer at a width and height different from the fixed sizes indicated.
7.2.4.8

Inheritance of layer properties

Table 7 summarizes how the properties of an enclosing parent <Layer> element are inherited by child <Layer>
elements. Properties may be not inherited at all, or inherited as-is, or replaced if the child redefines them, or
inherited and added to if the child also defines them
In Table 7, the number column states the number of times each element may appear in a Layer, either explicitlyor though inheritance. Thus, it is more restrictive than the constraints enforced by the schema in E.1. The
meanings of the values in this column are as follows:⎯ 1:

appears exactly once in each Layer.

⎯ 0/1: appears either once or not at all.
⎯ 0+: appears zero or more times.
⎯ 1+: appears one or more times.
The Inheritance column indicates whether or how the element is inherited by child Layers. The meanings of thevalues in this column are as follows:⎯ no: Not inherited. If the element is defined to be mandatory by this International Standard, then each Layerelement shall include that element.
⎯ replace: Value can be inherited from parent and omitted by child, but if specified by child then the parent
value is ignored.

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OGC 06-042⎯ add: Values can be inherited from parent and omitted by child. “Add” is only relevant for elements that may
appear more than one time. Child inherits any value(s) supplied by parent and adds any value(s) of its own to
the list. Any duplicated definition by the child is ignorable.
Table 7 — Inheritance of Layer properties
Element

7.2.5

NumberInheritance

Layer

0+

no

Name

0/1 a

no

Title

1

no

Abstract

0/1

noKeywordList

0/1

no

Style

0+

add

CRS

1+ b

add

EX_GeographicBoundingBox

1b

replace

BoundingBox

1+ b

replace

Dimension0+

replace

Attribution

0/1

replace

AuthorityURL

0+

add

Identifier

0+

noMetadataURL

0+no

DataURL

0/1

noFeatureListURL

0/1

no

MinScaleDenominator,
MaxScaleDenominator

0/1

replace

Attributes listed in Table 6

0/1

replacea

See 7.2.4.6.3 regarding distinction between named and unnamed layers.

b

May be 0 only if a value is inherited from an enclosing Layer element; see 7.2.4.6.6 through 7.2.4.6.8.

Format specifiers

Format specifiers appear in several places in service metadata: as valid output formats for an operation, as
supported Exception formats, and as the format of content at external URLs. Output formats are discussed in 6.6.

7.3

GetMap (mandatory)

7.3.1

GeneralThe GetMap operation returns a map. Upon receiving a GetMap request, a WMS shall either satisfy the requestor issue a service exception.

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7.3.2

GetMap request overview

Table 8 describes the query part of the GetMap request.

Table 8 — The Parameters of a GetMap request
Request parameter

Mandatory/optional

Description

VERSION=1.3.0

M

Request version.

REQUEST=GetMap

M

Request name.

LAYERS=layer_list

M

Comma-separated list of one or more map layers.

STYLES=style_list

M

Comma-separated list of one rendering style per requested
layer.

CRS=namespace:identifier

M

Coordinate reference system.

BBOX=minx,miny,maxx,maxy

M

Bounding box corners (lower left, upper right) in CRS units.

WIDTH=output_width

M

Width in pixels of map picture.

HEIGHT=output_heightM

Height in pixels of map picture.

FORMAT=output_format

M

Output format of map.

TRANSPARENT=TRUE|FALSE

O

Background transparency of map (default=FALSE).

BGCOLOR=color_value

O

Hexadecimal red-green-blue colour value for the backgroundcolor (default=0xFFFFFF).

EXCEPTIONS=exception_format

O

The format in which exceptions are to be reported by the
WMS (default=XML).

TIME=timeO

Time value of layer desired.

ELEVATION=elevationO

Elevation of layer desired.

Other sample dimension(s)O

Value of other dimensions as appropriate.

7.3.3
7.3.3.1

Request parameters
VERSION

The mandatory VERSION parameter is defined in 6.9.1. The value “1.3.0” shall be used for GetMap requests thatcomply with this International Standard.
7.3.3.2

REQUEST

The mandatory REQUEST parameter is defined in 6.9.2. To invoke the GetMap operation, the value “GetMap”
shall be used.
7.3.3.3

LAYERS

The mandatory LAYERS parameter lists the map layer(s) to be returned by this GetMap request. The value of the
LAYERS parameter is a comma-separated list of one or more valid layer names. Allowed layer names are thecharacter data content of any <Layer><Name> element in the service metadata.

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A WMS shall render the requested layers by drawing the leftmost in the list bottommost, the next one over that,and so on.
The optional <LayerLimit> element in the service metadata is a positive integer indicating the maximum number oflayers a client is permitted to include in a single GetMap request. If this element is absent, the server imposes nolimit.
7.3.3.4

STYLES

The mandatory STYLES parameter lists the style in which each layer is to be rendered. The value of the STYLES
parameter is a comma-separated list of one or more valid style names. There is a one-to-one correspondence
between the values in the LAYERS parameter and the values in the STYLES parameter. Each map in the list of
LAYERS is drawn using the corresponding style in the same position in the list of STYLES. Each style Name shallbe one that was defined in a <Style><Name> element that is either directly contained within, or inherited by, theassociated <Layer> element in service metadata. (In other words, the client may not request a Layer in a Style
that was only defined for a different Layer.) A server shall throw a service exception (code = StyleNotDefined) if
an unadvertised Style is requested. A client may request the default Style using a null value (as in “STYLES=”). If
several layers are requested with a mixture of named and default styles, the STYLES parameter shall include nullvalues between commas (as in “STYLES=style1,,style2,,”). If all layers are to be shown using the default style,either the form “STYLES=” or “STYLES=,,,” is valid.
If the server advertises several styles for a layer, and the client sends a request for the default style, the choice of
which style to use as default is at the discretion of the server. The ordering of styles in the service metadata does
not indicate which is the default.
7.3.3.5

CRS

The CRS request parameter states what Layer CRS (see 6.7.3) applies to the BBOX request parameter. The
value of the CRS parameter in a request to a particular server shall be one of the values defined in that server’s
service metadata in a <CRS> element defined or inherited by the requested layer. The same CRS applies to alllayers in a single request.
A WMS server is not required to support all possible CRSs, but it shall advertise in its service metadata those
CRSs which it does offer and shall accept requests for all advertised CRSs. If a request contains a CRS notoffered by a particular server, the server shall throw a service exception (code = “InvalidCRS”).
Clients are not required to support all possible CRSs. If a client and server do not support any mutually agreeable
CRSs, the client may, at its discretion, cease communicating with that server, or search for an intermediaryservice provider that performs coordinate transformations, or allow the user to choose other disposition methods.
This International Standard does not define a facility for clients to explicitly request reprojection or coordinatetransformation. That is, only a single CRS request parameter is defined, so it is not possible to specify a source
CRS for selecting geographic information and a different target CRS for the portrayal output. Reprojection may
occur implicitly, however, if the server offers multiple CRSs but internally stores its geographic information in aparticular CRS.
If the WMS server has declared CRS=CRS:1 for a Layer, as discussed in 6.7.3.5, then the Layer does not have awell-defined coordinate reference system and should not be shown in conjunction with other layers. The client
shall specify CRS=CRS:1 in the GetMap request and the server may issue a service exception otherwise. When
this CRS is used in the request, the BBOX parameter units shall be pixels.

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7.3.3.6

BBOX

The mandatory BBOX parameter allows a client to request a particular Bounding Box. Bounding Boxes aredefined in 6.7.4. The value of the BBOX parameter in a GetMap request is a list of comma-separated real
numbers (see 6.5) in the form "minx,miny,maxx,maxy". These values specify the minimum X, minimum Y,
maximum X, and maximum Y values of a region in the Layer CRS of the request. The units, ordering and directionof increment of the x and y axes are as defined by the Layer CRS (see 6.7.3) The four bounding box values
indicate the outside limits of the region. The relation of the Bounding Box to the map pixel matrix is that thebounding box goes around the “outside” of the pixels of the map rather than through the centres of the map’sborder pixels. In this context, individual pixels represent an area on the ground.
If a request contains an invalid BBOX (e.g. one whose minimum X is greater than or equal to the maximum X, or
whose minimum Y is greater than or equal to the maximum Y) the server shall throw a service exception.
If a request contains a BBOX whose area does not overlap at all with the <BoundingBox> element in the service
metadata for the requested layer, the server shall return empty content (that is, a blank map or an graphic
element file with no elements) for that map. Any features that are partly or entirely contained in the Bounding Box
shall be returned in the appropriate format.
If the Bounding Box values are not defined for the given CRS (e.g. latitudes greater than 90 degrees in CRS:84),
the server should return empty content for areas outside the valid range of the CRS.
If the WMS server has declared that a Layer is not subsettable, as described in 7.2.4.7.5, then the client shallspecify exactly the declared Bounding Box values in the GetMap request and the server may issue a service
exception otherwise.
7.3.3.7

FORMAT

The mandatory FORMAT parameter states the desired format of the map. Supported values for a GetMap request
on a WMS server are listed in one or more <Request><GetMap><Format> elements of its service metadata. The
entire MIME type string in <Format> is used as the value of the FORMAT parameter. There is no default format.
In an HTTP environment, the MIME type shall be set on the returned object using the Content-type entity header.
If the request specifies a format not supported by the server, the server shall issue a service exception (code =InvalidFormat).
7.3.3.8

WIDTH, HEIGHT

The mandatory WIDTH and HEIGHT parameters specify the size in integer pixels of the map to be produced. The
Map CS (see 6.7.2 and B.2) applies to the map. WIDTH-1 specifies the maximum value of the i axis in the Map
CS, and HEIGHT-1 specifies the maximum value of the j axis in the Map CS.
If the request is for a picture format, the returned picture, regardless of its MIME type, shall have exactly the
specified width and height in pixels. In the case where the aspect ratio of the BBOX and the ratio width/height are
different, the WMS shall stretch the returned map so that the resulting pixels could themselves be rendered in the
aspect ratio of the BBOX. In other words, it shall be possible using this definition to request a map for a device
whose output pixels are themselves non-square, or to stretch a map into an image area of a different aspect ratio.
Map distortions will be introduced if the aspect ratio WIDTH/HEIGHT is not commensurate with X, Y and the pixel
aspect. Client developers should minimize the possibility that users will inadvertently request or unknowingly
receive distorted maps.
If a request is for a graphic element format that does not have explicit width and height, the client shall include the
WIDTH and HEIGHT values in the request and a server may use them as helpful information in constructing theoutput map.

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The optional <MaxWidth> and <MaxHeight> elements in the service metadata are integers indicating the
maximum width and height values that a client is permitted to include in a single GetMap request. If either element
is absent, the server imposes no limit on the corresponding parameter.
If the WMS server has declared that a Layer has fixed width and height, as described in 7.2.4.7.5, then the client
shall specify exactly those WIDTH and HEIGHT values in the GetMap request and the server may issue a service
exception otherwise.
7.3.3.9

TRANSPARENTThe optional TRANSPARENT parameter specifies whether the map background is to be made transparent or not.
TRANSPARENT can take on two values, "TRUE" or "FALSE". The default value is FALSE if this parameter isabsent from the request.
The ability to return pictures drawn with transparent pixels allows results of different Map requests to be overlaid,producing a composite map. It is strongly recommended that every WMS offer a format that provides
transparency for layers that could sensibly be overlaid above others.
NOTE
The image/gif format provides transparency and is properly displayed by common web clients. The image/png
format provides a range of transparency options but support in viewing applications is less common. The image/jpeg format
does not provide transparency at all.

When TRANSPARENT is set to TRUE and the FORMAT parameter contains a Picture format (e.g. image/gif), thena WMS shall return (when permitted by the requested format) a result where all of the pixels not representing
features or data values in that Layer are set to a transparent value. For example, a “roads” layer would betransparent wherever no road is shown. If the picture format does not support transparency, then the server shall
respond with a non-transparent image (in other words, it is not an error for the client to always request transparent
maps regardless of format). When TRANSPARENT is set to FALSE, non-data pixels shall be set to the value of
BGCOLOR (see 7.3.3.10).
When the Layer has been declared “opaque” as in 7.2.4.7.4, then significant portions, or the entirety, of the map
may not be able to made transparent. Clients may still request TRANSPARENT=true.
When the FORMAT parameter contains a Graphic Element format, the TRANSPARENT parameter may be
included in the request but its value shall be ignored by the WMS.
7.3.3.10

BGCOLORThe optional BGCOLOR parameter is a string that specifies the colour to be used as the background (non-data)
pixels of the map. The general format of BGCOLOR is a hexadecimal encoding of an RGB value where twohexadecimal characters are used for each of red, green, and blue colour values. The values can range between
00 and FF (0 and 255, base 10) for each. The format is 0xRRGGBB; either upper or lower case characters areallowed for RR, GG, and BB values. The “0x” prefix shall have a lower case “x”. The default value is 0xFFFFFF(corresponding to the colour white) if this parameter is absent from the request.
When FORMAT is a picture format, a WMS shall set the background pixels to the colour specified by BGCOLOR.
When FORMAT is a graphic element format (which does not have an explicit background), or a picture format, a
WMS should avoid use of the BGCOLOR value for foreground elements because they would not be visible
against a background picture of the same colour.
When the Layer has been declared as “opaque” as in 7.2.4.7.4 (or is an area-filling coverage despite the absenceof an “opaque” declaration), then significant portions, or the entirety, of the map may not show any background at
all.

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7.3.3.11

EXCEPTIONS

The optional EXCEPTIONS parameter is defined in 6.9.4. The default value is “XML” if this parameter is absent
from the request.
A WMS shall offer one or more of the following exception reporting formats by listing them in separate <Format>
elements inside the <Exceptions> element of its service metadata. The first of these formats must be offered byevery WMS; the others are optional.
XML (mandatory)
Errors are reported using service exception XML, as specified in E.2. This is the default exception format if noneis specified in the request.
The remaining exception formats are optional. A server may issue a service exception in the default XML format if
a request specifies a different exception format not supported by the server.
INIMAGE (optional)
If the EXCEPTIONS parameter is set to INIMAGE, the WMS shall, upon detecting an error, return an object of the
MIME type specified in the FORMAT parameter whose content includes text describing the nature of the error. In
the case of a picture format, the error message shall be drawn on the returned picture. In the case of a graphic
element format, the text of the error message shall be rendered in the manner that text is normally represented inthat format.
BLANK (optional)
If the EXCEPTIONS parameter is set to BLANK, the WMS shall, upon detecting an error, return an object of thetype specified in FORMAT whose content is uniformly “off”. In the case of a picture format, that response shall be
an image containing only pixels of one colour (the background colour). In the case of a picture format supportingtransparency, if TRANSPARENT=TRUE is specified the pixels shall all be transparent. In the case of a graphic
element output format, no visible graphic elements shall be included in the response output.
7.3.3.12TIME

The use of Time values is specified in 6.7.6 and in Annexes C and D.
7.3.3.13

ELEVATION

The use of Elevation values is specified in 6.7.5 and in Annex C.
7.3.3.14

Other sample dimensions

The use of sample dimension values is specified in 6.7.7 and in Annex C.
7.3.4

GetMap response

The response to a valid GetMap request shall be a map of the spatially referenced information layer requested, inthe desired style, and having the specified coordinate reference system, bounding box, size, format andtransparency.
An invalid GetMap request shall yield an error output in the requested Exceptions format (or a network protocol
error response in extreme cases).

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In an HTTP environment, the MIME type of the returned value’s Content-type entity header shall match the formatof the return value.
7.3.5

Projection of geographic CRSs into Map CS

When the CRS parameter specifies a geographic coordinate reference system (such as CRS:84 or EPSG:4326),
the spatial data is internally projected using the Pseudo Plate Carrée coordinate operation method and thereafter
transformed to an image coordinate reference system with the i axis parallel and proportional to longitude and thej axis parallel and proportional to latitude to enable direct screen rendering. Because increments of latitude andlongitude are both not consistent in linear terms, the image axes are then of variable scale. The geographic
information is projected during the portrayal operation using a modified equidistant cylindrical projection as
follows:⎯ The minimum and maximum values of longitude and latitude requested (min_lon, min_lat, max_lon, max_lat)
are determined from the BBOX parameter, taking into account the x and y axis order specified by the CRS
parameter.
⎯ The angular distance (max_lon - min_lon) in degrees is scaled to the number of pixels specified by the
WIDTH parameter.
⎯ The angular distance (max_lat - min_lat) in degrees is scaled to the number of pixels specified by the
HEIGHT parameter.
⎯ The map is produced with longitude parallel to the i axis and latitude parallel to the j axis.

7.4

GetFeatureInfo (optional)

7.4.1

General

GetFeatureInfo is an optional operation. It is only supported for those Layers for which the attribute queryable="1"(true) has been defined or inherited. A client shall not issue a GetFeatureInfo request for other layers. A WMS
shall respond with a properly formatted service exception (XML) response (code = OperationNotSupported) if it
receives a GetFeatureInfo request but does not support it.
The GetFeatureInfo operation is designed to provide clients of a WMS with more information about features in the
pictures of maps that were returned by previous Map requests. The canonical use case for GetFeatureInfo is thata user sees the response of a Map request and chooses a point (I,J) on that map for which to obtain more
information. The basic operation provides the ability for a client to specify which pixel is being asked about, whichlayer(s) should be investigated, and what format the information should be returned in. Because the WMS
protocol is stateless, the GetFeatureInfo request indicates to the WMS what map the user is viewing by including
most of the original GetMap request parameters (all but VERSION and REQUEST). From the spatial context
information (BBOX, CRS, WIDTH, HEIGHT) in that GetMap request, along with the I,J position the user chose,
the WMS can (possibly) return additional information about that position.
The actual semantics of how a WMS decides what to return more information about, or what exactly to return, areleft up to the WMS provider.

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7.4.2

GetFeatureInfo request overview

The parameters of a GetFeatureInfo request are listed in Table 9.

Table 9 — The Parameters of a GetFeatureInfo Request
Request parameter

Mandatory/optional

Description

VERSION=1.3.0

M

Request version.

REQUEST=GetFeatureInfo

M

Request name.

map request partM

Partial copy of the Map request parameters that generated
the map for which information is desired.

QUERY_LAYERS=layer_list

M

Comma-separated list of one or more layers to be queried.

INFO_FORMAT=output_format

M

Return format of feature information (MIME type).

FEATURE_COUNT=number

O

Number of features about which to return information(default=1).

I=pixel_columnM

i coordinate in pixels of feature in Map CS.

J=pixel_row

M

j coordinate in pixels of feature in Map CS.

EXCEPTIONS=exception_format

O

The format in which exceptions are to be reported by the
WMS (default= XML).

7.4.3
7.4.3.1

Request parameters
VERSION

The mandatory VERSION parameter is defined in 6.9.1. The value “1.3.0” shall be used for GetFeatureInfo
requests that comply with this International Standard.
7.4.3.2

REQUEST

The mandatory REQUEST parameter is defined in 6.9.2. For GetFeatureInfo, the value “GetFeatureInfo” shall be
used.
7.4.3.3

Map request part

The mandatory “map request part” entry in Table 9 represents a sequence of parameters from the GetMap
request that generated the original map. Two of the GetMap parameters are omitted because GetFeatureInfo
provides its own values: VERSION and REQUEST. The remainder of the GetMap request shall be embedded
contiguously in the GetFeatureInfo request.
7.4.3.4

QUERY_LAYERS

The mandatory QUERY_LAYERS parameter states the map layer(s) from which feature information is desired tobe retrieved. Its value is a comma-separated list of one or more map layers. This parameter shall contain at least
one layer name, but may contain fewer layers than the original GetMap request.
If any layer in the QUERY_LAYERS parameter is not defined in the service metadata of the WMS, the server
shall issue a service exception (code = LayerNotDefined).

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7.4.3.5

INFO_FORMAT

The mandatory INFO_FORMAT parameter indicates what format to use when returning the feature information.
Supported values for a GetFeatureInfo request on a WMS server are listed as MIME types in one or more
<Request><FeatureInfo><Format> elements of its service metadata. The entire MIME type string in <Format> isused as the value of the INFO_FORMAT parameter. In an HTTP environment, the MIME type shall be set on the
returned object using the Content-type entity header. If the request specifies a format not supported by the server,
the server shall issue a service exception (code = InvalidFormat).
EXAMPLE

7.4.3.6

The parameter INFO_FORMAT=text/xml requests that the feature information be formatted in XML.

FEATURE_COUNTThe optional FEATURE_COUNT parameter states the maximum number of features per layer for which feature
information shall be returned. Its value is a positive integer. The default value is 1 if this parameter is omitted or isother than a positive integer.
7.4.3.7

I, J

The mandatory I and J request parameters are integers that indicate a point of interest on the map that was
produced by the embedded GetMap request (the “map request part” described in 7.4.3.3). The point (I,J) is apoint in the (i,j) space defined by the Map CS (see 6.7.2). Therefore:⎯ the value of I shall be between 0 and the maximum value of the i axis;⎯ the value of J shall be between 0 and the maximum value of the j axis;⎯ the point I=0, J=0 indicates the pixel at the upper left corner of the map;
⎯ I increases to the right and J increases downward.
The point (I,J) represents the centre of the indicated pixel.
If the value of I or of J is invalid, the server shall issue a service exception (code = InvalidPoint).
7.4.3.8

EXCEPTIONS

The optional EXCEPTIONS parameter is defined in 6.9.4. If this parameter is absent from the request, the default
value is "XML". No other values are defined by this International Standard for the WMS GetFeatureInfo request.
7.4.4

GetFeatureInfo response

The server shall return a response according to the requested INFO_FORMAT if the request is valid, or issue aservice exception otherwise. The nature of the response is at the discretion of the service provider, but it shallpertain to the feature(s) nearest to (I,J).

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Annex A(normative)
Conformance tests

A.1 Basic WMS
A.1.1 Basic WMS client
A.1.1.1

Basic service elements

Information for the basis service elements is as follows:a)

Test Purpose: Verify that a WMS client satisfies the requirements for request parameter rules.

b)

Test Method: Generate an adequate sample of requests from the client and verify that each is a valid request.

c)Reference: 6.3, 6.5, 6.6, 6.7

d)Test Type: Basic

A.1.1.2

GetCapabilities request

Information for the GetCapabilities request is as follows:a)

Test Purpose: Verify that a basic WMS client satisfies all requirements for a GetCapabilities request.

b)

Test Method: Generate an adequate sample of GetCapabilities requests from the client and verify that eachis a valid request.

c)Reference: 7.2

d)Test Type: Basic

A.1.1.3

GetMap request

Information for the GetMap request is as follows:a)

Test Purpose: Verify that a basic WMS client satisfies all requirements for a GetMap request.

b)

Test Method: Generate an adequate sample of GetMap requests from the client and verify that each is a valid
request.

c)

Reference: 7.3

d)Test Type: Basic

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A.1.2 Basic WMS server
A.1.2.1

Version negotiation

Information for the version negotiation is as follows:a)

Test Purpose: Verify that a basic WMS server satisfies the requirements for version negotiation.

b)

Test Method: Submit requests containing version numbers both lower than and higher than the version
supported by the server. Verify that the server responses are in accord with the rules for version negotiation.

c)Reference: 6.2

d)Test Type: Basic

A.1.2.2

Request parameter rules

Information for the request parameter rules is as follows:a)

Test Purpose: Verify that a basic WMS server satisfies the requirements for request parameter rules.

b)

Test Method: Generate a sample of requests from a client. Include both invalid requests and valid requestthat vary within the limits allowed by the rules. Verify that the server provides an appropriate response ineach case.

c)Reference: 6.3, 6.4, 6.5, 6.6, 6.7

d)Test Type: Basic

A.1.2.3

GetCapabilities response

Information for the GetCapabilities response is as follows:a)

Test Purpose: Verify that a basic WMS server satisfies all requirements of the GetCapabilities operation.

b)

Test Method: Make several GetCapabilities requests using a variety of input parameters. Verify that an
appropriate response is returned in each case.

c)Reference: 7.2

d)Test Type: Basic

A.1.2.4

GetMap response

Information for the GetMap response is as follows:a)

Test Purpose: Verify that a basic WMS client satisfies all requirements of the GetMap operation.

b)

Test Method: Make several GetMap requests using a variety of input parameters. Verify that an appropriate
response is returned in each case.

c)Reference: 7.3

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d)Test Type: Basic

A.2 Queryable WMS
A.2.1 Client for queryable WMS – GetFeatureInfo request
Information for the GetFeatureInfo request is as follows:a)

Test Purpose: Verify that a basic WMS client satisfies all requirements for a GetFeatureInfo request.

b)

Test Method: Generate an adequate sample of GetFeatureInfo requests from the client and verify that each isa valid request.

c)Reference: 7.4

d)Test Type: Basic

A.2.2 Queryable WMS server – GetFeatureInfo response
Information for the GetFeatureInfo response is as follows:a)

Test Purpose: Verify that a WMS interface satisfies all requirements for the operation GetFeatureInfo.

b)

Test Method: Make several GetFeatureInfo requests using a variety of input parameters. Verify that an
appropriate response is returned in each case.

c)Reference: 7.4

d)Test Type: Basic

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Annex B
(normative)CRS Definitions

B.1 Introduction
This annex defines several coordinate systems, including the Map CS (see 6.7.2), several Layer CRSs in the“CRS” namespace (see 6.7.3.2) and AUTO2 namespace (see 6.7.3.4), and a Vertical CRS (see 6.7.5). (Layer
CRSs in the "EPSG" namespace are defined by the European Petroleum Survey Group, as described in 6.7.3.3).
All of the Layer CRSs and Vertical CRSs defined in this annex (or by another authority such as EPSG) are
optional; the choice of which CRSs to support is at the discretion of the WMS provider. However, support for the
Map CS defined in B.2 is mandatory, because that CS applies to the output map generated by the WMS.
The definitions in this annex use either ISO 19111 tabular format (Tables B.1 to B.5) or ISO 19125 [5] Well-Known
Text representations.

B.2 Map CS (CRS:1)

Table B.1 — Definition of map coordinate system
Element name

Entry

Coordinate system identifier

CRS:1

Coordinate system type

Cartesian

Datum identifiercomputer display

Datum typeengineering

Coordinate system dimension

2

Coordinate system axis namei

Coordinate system axis direction

east

Coordinate system axis unit identifier

pixel

Coordinate system axis namej

Coordinate system axis direction

south

Coordinate system axis unit identifier

pixel

Coordinate system remarks

Origin is in upper left. Axis
values are non-negative
integers.

44

Comment
See 6.7.2

Some maps, especially over the poles, may
not have a well-defined linear axis direction.

Some maps, especially over the poles, may
not have a well-defined linear axis direction.

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B.3 Layer CRS using WGS 84 longitude-latitude (CRS:84)
Table B.2 — Definition of Layer CRS using WGS 84 longitude-latitude
Element name

Entry

Coordinate reference system kind code

1

Coordinate reference system identifier

CRS:84

Coordinate reference system valid area

world

Datum identifier

WGS 84

Datum typegeodetic

Prime meridian identifier

GreenwichPrime meridian Greenwich longitude

0 degreeEllipsoid identifier

WGS 84

Ellipsoid semi-major axis

6378137.0 m

Ellipsoid shapetrue

Ellipsoid inverse flattening

298.257223563

Coordinate system identifier

Geodetic Coordinate System

Coordinate system typegeodetic

Coordinate system dimension

2

Coordinate system axis namelongitude

Coordinate system axis direction

east

Coordinate system axis unit identifier

degreeCoordinate axis minimum value−180 degrees

Coordinate axis maximum value

180 degrees

Coordinate system axis namelatitude

Coordinate system axis direction

northCoordinate system axis unit identifier

degreeCoordinate axis minimum value−90 degrees

Coordinate axis maximum value

90 degrees

Comment
Single (not compound) CRS

The first (x) axis is longitude in this CRS.

The second (y) axis is latitude in this CRS.

NOTE
CRS:84 is permitted to be used at large scales (>10m/pixel) for describing or requesting map layers in any lon/lat
CRS that is equivalent to within ~1m.

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B.4 Layer CRS using NAD83 longitude-latitude (CRS:83)

Table B.3 — Definition of Layer CRS using NAD83 longitude-latitude
Element name

Entry

Coordinate reference system kind code

1

Coordinate reference system identifier

CRS:83

Coordinate reference system valid area

North America

Datum identifier

NAD83

Datum typegeodetic

Prime meridian identifier

GreenwichPrime meridian Greenwich longitude

0 degreeEllipsoid identifier

GRS80

Ellipsoid semi-major axis

6378137.0 m

Ellipsoid shapetrue

Ellipsoid inverse flattening

298.257222101

Coordinate system identifier

Geodetic Coordinate System

Coordinate system typegeodetic

Coordinate system dimension

2

Coordinate system axis namelongitude

Coordinate system axis direction

east

Coordinate system axis unit identifier

degreeCoordinate axis minimum value−180 degrees

Coordinate axis maximum value

180 degrees

Coordinate system axis namelatitude

Coordinate system axis direction

northCoordinate system axis unit identifier

degreeCoordinate axis minimum value−90 degrees

Coordinate axis maximum value

90 degrees

Comment
Single (not compound) CRS

The first (x) axis is longitude in this CRS

The second (y) axis is latitude in this CRS

NOTEThis is an optional Layer CRS. See CRS valid area above. Within this area some applications may require analternative system.

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B.5 Layer CRS using NAD27 longitude-latitude (CRS:27)

Table B.4 — Definition of Layer CRS using NAD27 longitude-latitude
Element name

Entry

Coordinate reference system kind code

1

Coordinate reference system identifier

CRS:27

Coordinate reference system valid area

North America

Datum identifier

NAD27

Datum typegeodetic

Prime meridian identifier

GreenwichPrime meridian Greenwich longitude

0 degreeEllipsoid identifier

Clarke 1866

Ellipsoid semi-major axis

6378206.4 m

Ellipsoid shapetrue

Ellipsoid inverse flattening

294.9786982

Coordinate system identifier

Geodetic Coordinate System

Coordinate system typegeodetic

Coordinate system dimension

2

Coordinate system axis namelongitude

Coordinate system axis direction

east

Coordinate system axis unit identifier

degreeCoordinate axis minimum value−180 degrees

Coordinate axis maximum value

180 degrees

Coordinate system axis namelatitude

Coordinate system axis direction

northCoordinate system axis unit identifier

degreeCoordinate axis minimum value−90 degrees

Coordinate axis maximum value

90 degrees

Comment
Single (not compound) CRS

The first (x) axis is latitude in this CRS

The second (y) axis is longitude in this CRS

NOTEThis is an optional Layer CRS. See CRS valid area above. Within this area, some applications may require analternative system.

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B.6 Vertical CRS using NAVD 88 (CRS:88)

Table B.5 — Definition of Vertical CRS using NAVD 88
Element name

Entry

Coordinate reference system kind code

1

Coordinate reference system identifier

CRS:88

Coordinate reference system valid area

North America

Datum identifier

North American Vertical Datum
1988

Datum typeverticalCoordinate system identifier

orthometric height

Coordinate system typegravity-related height

Coordinate system dimension

1

Coordinate system axis nameH

Coordinate system axis direction

up

Coordinate system axis unit identifier

meter

Comment

NOTE
This is an optional vertical CRS. See CRS valid area above. Within this area some applications may require analternative system.

B.7 Auto universal transverse mercator Layer CRS (AUTO2:42001)
In the notation below, "${var}" denotes a reference to the value of a variable "var". The variables "lat0" and"lon0" are the central point of the projection appearing in the CRS parameter of the map request (see 6.7.3.4).
The coordinate operation method uses ellipsoidal formulas.
PROJCS["WGS 84 / Auto UTM",GEOGCS["WGS 84",
DATUM["WGS_1984",
SPHEROID["WGS_1984", 6378137, 298.257223563]],
PRIMEM["Greenwich", 0],
UNIT["Decimal_Degree", 0.0174532925199433]],
PROJECTION["Transverse_Mercator"],PARAMETER["Latitude_of_Origin", 0],
PARAMETER["Central_Meridian", ${central_meridian}],
PARAMETER["False_Easting", 500000],
PARAMETER["False_Northing", ${false_northing}],
PARAMETER["Scale_Factor", 0.9996],
UNIT["Meter", 1]]
where${zone} = min( floor( (${lon0} + 180.0) / 6.0 ) + 1, 60 )${central_meridian} = -183.0 + ${zone} * 6.0

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OGC 06-042${false_northing} = (${lat0} >= 0.0) ? 0.0 : 10000000.0

B.8 Auto transverse mercator Layer CRS (AUTO2:42002)
In the notation below, "${var}" denotes a reference to the value of a variable "var". The variables "lat0" and"lon0" are the central point of the projection appearing in the CRS parameter of the map request (see 6.7.3.4).
The coordinate operation method uses ellipsoidal formulas.
PROJCS["WGS 84 / Auto Tr. Mercator",
GEOGCS["WGS 84",
DATUM["WGS_1984",
SPHEROID["WGS_1984", 6378137, 298.257223563]],
PRIMEM["Greenwich", 0],
UNIT["Decimal_Degree", 0.0174532925199433]],
PROJECTION["Transverse_Mercator"],PARAMETER["Latitude_of_Origin", 0],
PARAMETER["Central_Meridian", ${central_meridian}],
PARAMETER["False_Easting", 500000],
PARAMETER["False_Northing", ${false_northing}],
PARAMETER["Scale_Factor", 0.9996],
UNIT["Meter", 1]]
where${central_meridian} = ${lon0}${false_northing} = (${lat0} >= 0.0) ? 0.0 : 10000000.0

B.9 Auto orthographic Layer CRS (AUTO2:42003)
In the notation below, "${var}" denotes a reference to the value of a variable "var". The variables "lon0" and"lat0" are the central point of the projection appearing in the CRS parameter of the map request (see 6.7.3.4). The
coordinate operation method uses spherical formulas.
PROJCS["WGS 84 / Auto Orthographic",
GEOGCS["WGS 84",
DATUM["WGS_1984",
SPHEROID["WGS_1984", 6378137, 298.257223563]],
PRIMEM["Greenwich", 0],
UNIT["Decimal_Degree", 0.0174532925199433]],
PROJECTION["Orthographic"],
PARAMETER["Latitude_of_Origin", ${latitude_of_origin}],
PARAMETER["Central_Meridian", ${central_meridian}],
UNIT["Meter", 1]]
where${latitude_of_origin} = ${lat0}${central_meridian} = ${lon0}

B.10 Auto equirectangular Layer CRS (AUTO2:42004)
In the notation below, "${var}" denotes a reference to the value of a variable "var". The variables "lon0" and"lat0" are the central point of the projection appearing in the CRS parameter of the map request (see 6.7.3.4). The
coordinate operation method uses ellipsoidal formulas.

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PROJCS["WGS 84 / Auto Equirectangular",
GEOGCS["WGS 84",
DATUM["WGS_1984",
SPHEROID["WGS_1984", 6378137, 298.257223563]],
PRIMEM["Greenwich", 0],
UNIT["Decimal_Degree", 0.0174532925199433]],
PROJECTION["Equirectangular"],
PARAMETER["Latitude_of_Origin", 0],
PARAMETER["Central_Meridian", ${central_meridian}],
PARAMETER["Standard_Parallel_1", ${standard_parallel}],UNIT["Meter", 1]]
where${standard_parallel} = ${lat0}${central_meridian} = ${lon0}

B.11 Auto Mollweide Layer CRS (AUTO2:42005)
In the notation below, "${var}" denotes a reference to the value of a variable "var". The variables "lon0" and"lat0" are the central point of the projection appearing in the CRS parameter of the map request (see 6.7.3.4).
The coordinate operation method uses ellipsoidal formulas.
PROJCS["WGS 84 / Auto Mollweide",
GEOGCS["WGS 84",
DATUM["WGS_1984",
SPHEROID["WGS_1984", 6378137, 298.257223563]],
PRIMEM["Greenwich", 0],
UNIT["Decimal_Degree", 0.0174532925199433]],
PROJECTION["Mollweide"],PARAMETER["Central_Meridian", ${central_meridian}],
UNIT["Meter", 1]]
where${central_meridian} = ${lon0}50

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Annex C
(normative)
Handling multi-dimensional data

C.1 Overview
This annex describes support for multi-dimensional data in the service metadata and operation request
parameters of the WMS. “Dimensions” in this annex refers to Time, Elevation, and sample dimensions; horizontal
dimensions are expressed using Layer CRS (see 6.7.3). Optional elements in WMS metadata declare available
values along one or more dimensional axes applicable to a Layer. GetMap requests for that layer may include
parameters specifying dimensional value(s).
For example, consider a server that offers daily satellite composite images of the Earth. If the provision defined inthis annex for handling multi-dimensional data were not available, then the server could give each layer a different
name (e.g. by appending a string indicating the date to a base name), and a client would request the desired timeby supplying the appropriate name in the GetMap request. The number of layers in the service metadata wouldgrow during the lifetime of the satellite as new images were added to the server’s database. If the imagery werealso available in multiple wavelength bands, then number of layers would be the product of the number ofavailable times and bands. By following the provisions in this annex, a more compact representation of available
times and bands is possible. The server may declare a single name for the layer and enumerate available times
and wavelength bands in its service metadata. A client then adds additional parameters to the GetMap request to
request a specific time and band.

C.2 Declaring dimensions and their allowed values
The optional <Dimension> element is used in service metadata to declare that one or more dimensionalparameters are relevant to a layer or group of layers. Table C.1 shows the fields in a Dimension element: amandatory name, a mandatory measurement units specifier with an optional unitSymbol, a mandatory string
indicating available value(s) of the corresponding dimension, an optional default value used when the client does
not specify one, and several optional Boolean attributes indicating whether multiple values of the dimension may
be requested at the same time, whether the nearest available value of a dimension will be returned in response toa request for a nearby value, and in the case of temporal extents, whether the most recent map may be requested
without specifying its exact time.

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Table C.1 — Contents of a dimension element
Field

Mandatory/
optional

Meaning

nameM

Attribute stating name of dimensional axis.

units

M

Attribute indicating units of dimensional axis.

unitSymbol

O

Attribute specifying symbol.

defaultO

Attribute indicating default value that will be used if GetMap request does not specify
a value. If attribute is absent, then shall respond with a service exception if request
does not include a value for that dimension.

multipleValues

O

Boolean attribute indicating whether multiple values of the dimension may berequested. 0 (or “false”) = single values only; 1 (or “true”) = multiple values permitted.
Default = 0.

nearestValueO

Boolean attribute indicating whether nearest value of the dimension will be returned in
response to a request for a nearby value. 0 (or “false”) = request value(s) mustcorrespond exactly to declared extent value(s); 1 (or “true”) = request values may beapproximate. Default = 0.

current

O

Boolean attribute valid only for temporal extents (i.e. if attribute name="time"). This
attribute, if it either 1 or “true”, indicates (a) that temporal data are normally kept
current and (b) that the request parameter TIME may include the keyword “current”
instead of an ending value (see C.4.1). Default = 0.

extentM

Text content indicating available value(s) for dimension.

A Dimension element has the following format in XML:
<Dimension name="dimension_name" units=unit_name unitSymbol="symbol"
default="default_value" multipleValues="0|1" nearestValue="0|1"
current="0|1">extent</Dimension>
Dimension elements shall comply with the following rules:⎯ Dimension names shall be interpreted case-insensitively and should contain no whitespace.
⎯ If the dimensional quantity has no units (e.g. band number in a multi-wavelength sensor), use the null string:units="".
⎯ If the dimensional quantity has units, unit names should be taken from the Unified Code for Units of Measure(UCUM) if UCUM has an appropriate entry. When UCUM is used, the mandatory units attribute shall be an
appropriate entry from the UCUM “name” column.
⎯ If present, the unitSymbol shall be a 7-bit ASCII character string. When UCUM is used, the unitSymbol shallbe the entry from the UCUM “c/s” column (case-sensitive abbreviation) corresponding to the UCUM name.
UCUM prefix names and symbols may be present as well.
The extent string declares what value(s) along the Dimension axis are appropriate for the corresponding layer.
The extent string has the syntax shown in Table C.2.

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Table C.2 — Syntax for listing one or more extent values
SyntaxMeaningvalue

A single value.

value1,value2,value3,... aA list of multiple values.

min/max/resolution

An interval defined by its lower and upper bounds and its resolution.

min1/max1/res1,min2/max2/res2,... aA list of multiple intervals.

aWhitespace is allowed following commas in a list in a <Dimension> element of service metadata.

A resolution value of zero (as in min/max/0) means that the data are effectively at infinitely-fine resolution for the
purposes of making requests on the server. For instance, an instrument which continuously monitors randomlyoccurring data may have no explicitly defined temporal resolution.
All dimensions in a service metadata response are server-defined, with two exceptions. The dimensions named
time and elevation are special cases predefined as follows:<Dimension name="time" units="ISO8601" /><Dimension name="elevation" units="verticalCRSid" unitSymbol="symbol" />The time units identifier “ISO 8601” refers to the ISO 8601:2000 time representation specified in Annex D. No
unitSymbol is defined for the time dimension. If a server opts to specify time values in a different representation it
shall use a dimension name other than “time” (e.g. “date” or “seconds”).
The elevation units identifier “verticalCRSid” refers to a vertical CRS as in 6.7.5. The unitSymbol attribute shall bechosen to match the units of the specified vertical CRS.
EXAMPLE 1
The verticalCRSid “CRS:88” refers to the vertical CRS defined in B.6 (elevation in meters in the North
American Vertical Datum 1988). The unitSymbol “m” would be used.
EXAMPLE 2

The following are some examples of server-defined dimensions:<Dimension name="time" units="ISO8601" default="2003-10-17">1996-01-01/2003-10-17/P1D</Dimension><Dimension name="temperature" units="Kelvin" unitSymbol="K" default="300">230,300,400</Dimension><Dimension name="elevation" units="CRS:88" unitSymbol="m" default="0">0/10000/100</Dimension>

Dimension declarations are inherited by enclosed Layers, as specified in 7.2.4.8.
A layer may provide a dimension declaration that has the same name attribute (case-insensitive matching) as adeclaration in another layer. However, the dimension shall not be re-declared using the same name withconflicting units or unitSymbol attributes. Extent values, and the attributes default, nearestValue andmultipleValues, may be different for each layer.

C.3 Including dimensional values in a request
C.3.1 Introduction
Requests for a layer with one or more <Dimension> elements in its service metadata may require additionalparameters to formulate a complete GetMap query. This following subclauses specifies how clients shall include
dimensional parameters in the GetMap request.

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C.3.2 Elevation and time values in requests
If a data object has an Elevation dimension defined, then operation requests to retrieve that object may include
the parameter
ELEVATION=value.
If a Layer has a Time dimension defined, then requests may include the parameter
TIME=value.
In either case, value uses the format described in Table C.2 to provide a single value, a comma-separated list, oran interval of the form start/end without a resolution. value shall not contain white space. An interval in a request
value is a request for all the data from the start value up to and including the end value.
The absence of Time or Elevation parameters in the request is equivalent to a request for the Layer’s default
value (if defined) along that dimension (see C.4.2). All parameter names are case-insensitive as stated in 6.8.1,
so, for example, “TIME”, “Time” and “time” are all acceptable.
For the TIME parameter, the special keyword “current” may be used if the <Dimension name="time"> service
metadata element includes a nonzero value for the “current” attribute, as described in C.2. The expression“TIME=current” means “send the most current data available”. The expression “TIME=start_time/current” means“send data from start_time up to the most current data available”.

C.3.3 Sample dimension values in requests
Sample dimension parameters allow the client to request a particular layer along one or more dimensional axes
other than time or elevation.
A request parameter name is constructed by concatenating the prefix “dim_” with the sample dimension Name(the value of the name attribute of the corresponding <Dimension> element in the service metadata). The
resulting “dim_name” is case-insensitive. The use of the “dim_” prefix is to avoid clashes between server-defined
dimension names and other request parameters defined by this International Standard. (The “time” and“elevation” dimensions, being predefined, do not use the prefix.)
To include a sample dimension value in a request URL, the dim_name parameter is followed by an equals sign“=” and a valid value, a comma-separated list, or an interval, as described in Table C.2.
EXAMPLEA WMS Layer is described as having an extent along a dimension named “wavelength” as follows:<Dimension name="wavelength" units="Angstrom" unitSymbol="Ao">3000,4000,5000,6000<Dimension>.
A GetMap request for a portrayal of the data at 4000 Angstroms would include the parameter “DIM_WAVELENGTH=4000”.

A request may omit a dimension parameter, or use a null value, to request the default value (if supplied) alongthat dimension; see C.4.2.

C.3.4 Single- and multiple-valued requests
Whether a request for a spatially referenced object may include only a single value for each dimension or multiple
values depends on the context. Multiple values are only acceptable when both the output format and the nature of
the geographic information permit it. A server may include a nonzero multipleValue attribute in a Dimension
element to indicate that multi-valued requests are supported. A server shall issue a service exception (code =InvalidDimensionValue) if it cannot comply with the dimensional parameters as specified.
EXAMPLE 1
A WMS server offers maps in PNG image format of vehicle traffic density updated hourly. A valid GetMap
request would include only a single TIME to select the desired map.
EXAMPLE 2
A server offers daily ozone maps in QuickTime movie format. The movie can contain multiple frames, so a
valid GetMap request could include multiple times.

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EXAMPLE 3
A server offers maps showing crime locations. Each crime has an associated date. A GetMap image request
for all crimes occurring within a specific period would include a TIME range.

C.3.5 Applicability to multiple layers
The WMS GetMap request includes a comma-separated list of one or more Layers. In such a request, the TIME,ELEVATION and DIM_ parameters apply to all layers individually as follows:⎯ If the spatially referenced object has the corresponding dimension as a property, then the dimension value
applies as if that object had been requested alone.
⎯ If the spatially referenced object does not have that dimension, then the dimension value is ignored for the
purposes of responding to the request for that object.
EXAMPLEA client’s GetMap request includes “LAYERS=temperature,coastlines&TIME=2001-05-09” where“temperature” is a daily temperature map (for which time is relevant) and “coastlines” is a coastline map (which is static). The
WMS responds with the static coastlines drawn atop the temperature for the specified date, without issuing an exception
because TIME does not apply to its coastlines layer. If the date is invalid for the temperature layer, then the server may issue aservice exception (code = InvalidDimensionValue) to that effect.

C.3.6 Example requests
The following are example parameter value combinations for multi-dimensional GetMap requests.
EXAMPLE 1

Request for single ozone map at specified time and height:

VERSION=1.3.0
WIDTH=600
REQUEST=GetMap
HEIGHT=300
LAYERS=ozone
TIME=2000-08-03
CRS=CRS:84
ELEVATION=1000
BBOX=-180,-90,180,90 FORMAT=image/gif
EXAMPLE 2

Request for movie loop at specified frame times:

VERSION=1.3.0
WIDTH=600
REQUEST=GetMap
HEIGHT=300
LAYERS=ozone
TIME=2000-07-01/2000-07-31/P1D
CRS=CRS:84
ELEVATION=1000
BBOX=-180,-90,180,90 FORMAT=video/mpeg

C.4 Server responses
C.4.1 Incorrect values
If the dimension value is invalid or missing from the client request, and no default or nearest-value behaviour was
enabled as discussed in the following subclauses, then the server shall respond with a service exception (code =InvalidDimensionValue or code = MissingDimensionValue, as appropriate).

C.4.2 Default values
A WMS may declare a default for any dimension by including the “default” attribute in the <Dimension> element. A
default value is optional but recommended. If a request does not include a value along this dimension, and adefault has been declared, then the server shall send the default value. If there is no declared default, then theserver shall throw an Exception (code="MissingDimensionValue") to indicate that a value was required.

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In order that the client may determine what value was actually sent, the server shall label the response object withthe actual value used by default. In the HTTP environment, the labelling is performed using an HTTP response
header. For each dimension to which a default value was applied, a header line of the following form shall besent:
Warning: 99 Default value used: DIM_NAME=value units
where "99" is a defined by HTTP (IETF RFC 2616) for use by miscellaneous warnings, DIM_NAME is thecorresponding request parameter name, value is the value actually used, and units is the units attribute (see C.2)
for that dimension.

C.4.3 Nearest values
A WMS may declare that it will choose the closest available value for a dimension if an exact value is not
specified. This allows, for example, hourly data whose actual recording time is precise to the millisecond to berequested simply by stating the desired date and hour. The nearestValue attribute of the <Dimension> element, if
present and nonzero, indicates that this behaviour is enabled.
If a request includes an imprecise dimensional value, and nearest value behaviour has been declared, then theserver shall compute and send the nearest available value. The value shall be rounded, not merely truncated. If
nearestValue
selectionis
notsupported,thentheserver
shall
throw
an
Exception(code="InvalidDimensionValue") to indicate that a value was required.
In order that the client may determine what value was actually sent, the server shall label the response object withthe actual value found by rounding. In the HTTP environment, the labelling is performed using an HTTP response
header. For each dimension to which a rounded-off value was applied, a header line of the following form shall besent:
Warning: 99 Nearest value used: DIM_NAME=value units
where "99" is a defined by HTTP (IETF RFC 2616) for use by miscellaneous warnings, DIM_NAME is thecorresponding request parameter name, value is the value actually used, and units is the units attribute (see C.2)
for that dimension.

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Annex D(normative)
Web Map Service profile of ISO 8601

D.1 Overview
This Annex specifies the encoding of moments and periods in time to allow the Web Map Service to support
temporal data descriptions and requests. This Annex is based on ISO 8601 and extends ISO 8601 by defining a
syntax for expressing in a single string the start, end and periodicity of a data collection.

D.2 Time format details
D.2.1 Basic syntax
The basic time format uses ISO 8601:2000 “extended” format: up to 14 digits specifying century, year, month, day,hour, minute, and seconds, and optionally a decimal point followed by zero or more digits for fractional seconds,
with non-numeric characters to separate each piece:
ccyy-mm-ddThh:mm:ss.sssZ
The precision may be reduced by omitting least-significant digits, as in the examples below. ISO 8601:2000
prefers a decimal comma before fractional seconds but allows a decimal period as in this International Standard.
The century digits shall be included with the year; two-digit years shall not be used.
A time zone suffix is mandatory if the hours field appears in the time string. All times should be expressed in
Coordinated Universal Time (UTC), indicated by the suffix Z (for "zulu"). When a local time applies, a numerictime zone suffix as defined by ISO 8601:2004, 5.3.4.1 shall be used. The absence of any suffix at all means local
time in an undefined zone, which shall not be used in the global network of map servers enabled by thisInternational Standard.
EXAMPLE 1

ccyy

Year only

EXAMPLE 2

ccyy-mmYear and month

EXAMPLE 3

ccyy-mm-dd

Year, month and day

EXAMPLE 4

ccyy-mm-ddThhZYear, month, day and hour in UTC

D.2.2 Representation of years before 0001
As specified in ISO 8601, the year immediately preceding 0001 shall be denoted 0000. Years before 0000 shallbe denoted by a leading minus sign (hyphen character). To denote years in the distant past, the year field shall be
expanded beyond 4 digits and preceded by a minus sign.
EXAMPLE 1−1350(1350 “BC”, approximate time of Tutankhamen)

EXAMPLE 2−18000(last Ice Age, 18 thousand years ago)

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EXAMPLE 3−150000000(Jurassic period, 150 million years ago)

EXAMPLE 4−5000000000(Earth’s crust solidifies, 5000 million years ago)

D.3 Period format
An ISO 8601 Period is used to indicate the time resolution of the available data. The ISO 8601 format for
representing a period of time is used to represent the resolution: Designator P (for Period), number of years Y,
months M, days D, time designator T, number of hours H, minutes M, seconds S. Unneeded elements may beomitted.
EXAMPLE 1

P1Y — 1 year

EXAMPLE 2

P1M10D — 1 month plus 10 days

EXAMPLE 3

PT2H — 2 hours

EXAMPLE 4

PT1.5S — 1.5 seconds

D.4 Time lists and ranges
C.3 defines a syntax for representing single or multiple values of dimensions including time. Thus, a list of several
times is expressed by separating valid time values with a comma (“,”). A temporal range is expressed using thesyntax start/end/period to indicate the start time of the data, the ending time, and the time resolution or refreshrate. Data which are refreshed at regular intervals but not archived are represented using time/time/period, where
both time values are the same (that of the latest data) and the period indicates the refresh rate.
NOTE
This is an extension to ISO 8601:2000, which represents interval formats as start/end, or start/period, or
period/end, or period alone. ISO 19128 allows start/end/period, where “period” in this context means “periodicity” rather than“amount of time between start and end of interval”.

D.5 Examples
EXAMPLE 1

A single moment (scalar value): 2000-06-23T20:07:48.11Z

EXAMPLE 2

Quarterly data (comma-separated list): 1999-01-01,1999-04-01,1999-07-01,1999-10-01

EXAMPLE 3

Daily data taken at noon since 15 April 1995 (periodic interval):
1995-04-22T12:00Z/2000-06-21T12:00Z/P1D

EXAMPLE 4

Current data refreshed every 30 min (periodic interval): 2000-06-18T14:30Z/2000-06-18T14:30Z/PT30M

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Annex E
(normative)
XML Schemas

E.1 WMS Capabilities XML schemaThis annex contains the XML schema for WMS capabilities against which service metadata from a server
compliant with this International Standard may be validated. Comments and documentation elements in theschema are informative; in case of conflict with the main body of this International Standard, the main body takes
precedence. The schemaLocation attributes are also informative.
The schema may also be found on-line at <http://schemas.opengis.net/wms/1.3.0/>.
<?xml version="1.0" encoding="UTF-8"?><schema targetNamespace="http://www.opengis.net/wms"
xmlns="http://www.w3.org/2001/XMLSchema"
xmlns:wms="http://www.opengis.net/wms"
xmlns:xlink="http://www.w3.org/1999/xlink"elementFormDefault="qualified"><import namespace="http://www.w3.org/1999/xlink"
schemaLocation="http://schemas.opengis.net/gml/2.1.2/xlinks.xsd"/><!-- ********************************************************************* --><!-- ** The Top-Level Element.
** --><!-- ********************************************************************* --><element name="WMS_Capabilities"><annotation><documentation>
A WMS_Capabilities document is returned in response to a
GetCapabilities request made on a WMS.
</documentation></annotation><complexType><sequence><element ref="wms:Service"/><element ref="wms:Capability"/></sequence><attribute name="version" type="string" fixed="1.3.0"/><attribute name="updateSequence" type="string"/></complexType></element><!-- ********************************************************************* --><!-- ** Elements Used In Multiple Places.
** --><!-- ********************************************************************* --><element name="Name" type="string"><annotation><documentation>
The Name is typically for machine-to-machine communication.
</documentation></annotation></element><element name="Title" type="string"><annotation><documentation>

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The Title is for informative display to a human.
</documentation></annotation></element><element name="Abstract" type="string"><annotation><documentation>
The abstract is a longer narrative description of an object.
</documentation></annotation></element><element name="KeywordList"><annotation><documentation>
List of keywords or keyword phrases to help catalog searching.
</documentation></annotation><complexType><sequence><element ref="wms:Keyword" minOccurs="0" maxOccurs="unbounded"/></sequence></complexType></element><element name="Keyword"><annotation><documentation>
A single keyword or phrase.
</documentation></annotation><complexType><simpleContent><extension base="string"><attribute name="vocabulary" type="string" /></extension></simpleContent></complexType></element><element name="OnlineResource"><annotation><documentation>
An OnlineResource is typically an HTTP URL. The URL is placed in
the xlink:href attribute, and the value "simple" is placed in the
xlink:type attribute.
</documentation></annotation><complexType><attributeGroup ref="xlink:simpleLink"/></complexType></element><element name="Format" type="string"><annotation><documentation>
A container for listing an available format's MIME type.
</documentation></annotation></element><!-- ********************************************************************* --><!-- ** General Service Metadata.
** --><!-- ********************************************************************* --><element name="Service"><annotation><documentation>
General service metadata.
</documentation>

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OGC 06-042</annotation><complexType><sequence><element name="Name"><simpleType><restriction base="string"><enumeration value="WMS"/></restriction></simpletype></element><element ref="wms:Title"/><element ref="wms:Abstract" minOccurs="0"/><element ref="wms:KeywordList" minOccurs="0"/><element ref="wms:OnlineResource"/><element ref="wms:ContactInformation" minOccurs="0"/><element ref="wms:Fees" minOccurs="0"/><element ref="wms:AccessConstraints" minOccurs="0"/><element ref="wms:LayerLimit" minOccurs="0"/><element ref="wms:MaxWidth" minOccurs="0"/><element ref="wms:MaxHeight" minOccurs="0"/></sequence></complexType></element><element name="ContactInformation"><annotation><documentation>
Information about a contact person for the service.
</documentation></annotation><complexType><sequence><element ref="wms:ContactPersonPrimary" minOccurs="0"/><element ref="wms:ContactPosition" minOccurs="0"/><element ref="wms:ContactAddress" minOccurs="0"/><element ref="wms:ContactVoiceTelephone" minOccurs="0"/><element ref="wms:ContactFacsimileTelephone" minOccurs="0"/><element ref="wms:ContactElectronicMailAddress" minOccurs="0"/></sequence></complexType></element><element name="ContactPersonPrimary"><complexType><sequence><element ref="wms:ContactPerson"/><element ref="wms:ContactOrganization"/></sequence></complexType></element><element name="ContactPerson" type="string"/><element name="ContactOrganization" type="string"/><element name="ContactPosition" type="string"/><element name="ContactAddress"><complexType><sequence><element ref="wms:AddressType"/><element ref="wms:Address"/><element ref="wms:City"/><element ref="wms:StateOrProvince"/><element ref="wms:PostCode"/><element ref="wms:Country"/></sequence></complexType></element><element name="AddressType" type="string"/><element name="Address" type="string"/>

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OGC 06-042<element name="City" type="string"/><element name="StateOrProvince" type="string"/><element name="PostCode" type="string"/><element name="Country" type="string"/><element name="ContactVoiceTelephone" type="string"/><element name="ContactFacsimileTelephone" type="string"/><element name="ContactElectronicMailAddress" type="string"/><element name="Fees" type="string"/><element name="AccessConstraints" type="string"/><element name="LayerLimit" type="positiveInteger"/><element name="MaxWidth" type="positiveInteger"/><element name="MaxHeight" type="positiveInteger"/>62

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OGC 06-042<!-- ********************************************************************* --><!-- ** The Capability Element.
** --><!-- ********************************************************************* --><element name="Capability"><annotation><documentation>
A Capability lists available request types, how exceptions may bereported, and whether any extended capabilities are defined.
It also includes an optional list of map layers available from thisserver.
</documentation></annotation><complexType><sequence><element ref="wms:Request"/><element ref="wms:Exception"/><element ref="wms:_ExtendedCapabilities" minOccurs="0"
maxOccurs="unbounded"/><element ref="wms:Layer" minOccurs="0"/></sequence></complexType></element><!-- ********************************************************************* --><!-- ** The Request Element.
** --><!-- ********************************************************************* --><element name="Request"><annotation><documentation>
Available WMS Operations are listed in a Request element.
</documentation></annotation><complexType><sequence><element ref="wms:GetCapabilities"/><element ref="wms:GetMap"/><element ref="wms:GetFeatureInfo" minOccurs="0"/><element ref="wms:_ExtendedOperation" minOccurs="0" maxOccurs="unbounded"/></sequence></complexType></element><element name="GetCapabilities" type="wms:OperationType"/><element name="GetMap" type="wms:OperationType"/><element name="GetFeatureInfo" type="wms:OperationType"/><element name="_ExtendedOperation" type="wms:OperationType" abstract="true"/><complexType name="OperationType"><annotation><documentation>
For each operation offered by the server, list the available output
formats and the online resource.
</documentation></annotation><sequence><element ref="wms:Format" minOccurs="1" maxOccurs="unbounded"/><element ref="wms:DCPType" minOccurs="1" maxOccurs="unbounded"/></sequence></complexType><element name="DCPType"><annotation><documentation>
Available Distributed Computing Platforms (DCPs) are listed here.
At present, only HTTP is defined.
</documentation></annotation><complexType><sequence>

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OGC 06-042<element ref="wms:HTTP"/></sequence></complexType></element><element name="HTTP"><annotation><documentation>
Available HTTP request methods. At least "Get" shall be supported.
</documentation></annotation><complexType><sequence><element ref="wms:Get"/><element ref="wms:Post" minOccurs="0"/></choice></complexType></element><element name="Get"><annotation><documentation>
The URL prefix for the HTTP "Get" request method.
</documentation></annotation><complexType><sequence><element ref="wms:OnlineResource"/></sequence></complexType></element><element name="Post"><annotation><documentation>
The URL prefix for the HTTP "Post" request method.
</documentation></annotation><complexType><sequence><element ref="wms:OnlineResource"/></sequence></complexType></element><!-- ********************************************************************* --><!-- ** The Exception Element.
** --><!-- ********************************************************************* --><element name="Exception"><annotation><documentation>
An Exception element indicates which error-reporting formats aresupported.
</documentation></annotation><complexType><sequence><element ref="wms:Format" minOccurs="1" maxOccurs="unbounded"/></sequence></complexType></element><!-- ********************************************************************* --><!-- ** Extended Capabilities.
** --><!-- ********************************************************************* --><element name="_ExtendedCapabilities" abstract="true"><annotation><documentation>
Individual service providers may use this element to report extended

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capabilities.
</documentation></annotation></element><!-- ********************************************************************* --><!-- ** The Layer Element.
** --><!-- ********************************************************************* -->Copyright © 2006 Open Geospatial Consortium, Inc. All Rights Reserved.

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OGC 06-042<element name="Layer"><annotation><documentation>
Nested list of zero or more map Layers offered by this server.
</documentation></annotation><complexType><sequence><element ref="wms:Name" minOccurs="0"/><element ref="wms:Title"/><element ref="wms:Abstract" minOccurs="0"/><element ref="wms:KeywordList" minOccurs="0"/><element ref="wms:CRS" minOccurs="0" maxOccurs="unbounded"/><element ref="wms:EX_GeographicBoundingBox" minOccurs="0"/><element ref="wms:BoundingBox" minOccurs="0" maxOccurs="unbounded"/><element ref="wms:Dimension" minOccurs="0" maxOccurs="unbounded"/><element ref="wms:Attribution" minOccurs="0"/><element ref="wms:AuthorityURL" minOccurs="0" maxOccurs="unbounded"/><element ref="wms:Identifier" minOccurs="0" maxOccurs="unbounded"/><element ref="wms:MetadataURL" minOccurs="0" maxOccurs="unbounded"/><element ref="wms:DataURL" minOccurs="0" maxOccurs="unbounded"/><element ref="wms:FeatureListURL" minOccurs="0" maxOccurs="unbounded"/><element ref="wms:Style" minOccurs="0" maxOccurs="unbounded"/><element ref="wms:MinScaleDenominator" minOccurs="0"/><element ref="wms:MaxScaleDenominator" minOccurs="0"/><element ref="wms:Layer" minOccurs="0" maxOccurs="unbounded"/></sequence><attribute name="queryable" type="boolean" default="0"/><attribute name="cascaded" type="nonNegativeInteger"/><attribute name="opaque" type="boolean" default="0"/><attribute name="noSubsets" type="boolean" default="0"/><attribute name="fixedWidth" type="nonNegativeInteger"/><attribute name="fixedHeight" type="nonNegativeInteger"/></complexType></element><element name="CRS" type="string"><annotation><documentation>
Identifier for a single Coordinate Reference System (CRS).
</documentation></annotation></element><element name="EX_GeographicBoundingBox"><annotation><documentation>
The EX_GeographicBoundingBox attributes indicate the limits of the enclosing
rectangle in longitude and latitude decimal degrees.
</documentation></annotation><complexType><sequence><element name="westBoundLongitude" type="wms:longitudeType" /><element name="eastBoundLongitude" type="wms:longitudeType" /><element name="southBoundLatitude" type="wms:latitudeType" /><element name="northBoundLatitude" type="wms:latitudeType" /></sequence></complexType></element><element name="BoundingBox"><annotation><documentation>
The BoundingBox attributes indicate the limits of the bounding box
in units of the specified coordinate reference system.
</documentation></annotation><complexType><attribute name="CRS" type="string" use="required"/><attribute name="minx" type="double" use="required"/>66

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OGC 06-042<attribute name="miny" type="double" use="required"/><attribute name="maxx" type="double" use="required"/><attribute name="maxy" type="double" use="required"/><attribute name="resx" type="double"/><attribute name="resy" type="double"/></complexType></element><element name="Dimension"><annotation><documentation>
The Dimension element declares the existence of a dimension and indicates whatvalues along a dimension are valid.
</documentation></annotation><complexType><simpleContent><extension base="string"><attribute name="name" type="string" use="required"/><attribute name="units" type="string" use="required"/><attribute name="unitSymbol" type="string"/><attribute name="default" type="string"/><attribute name="multipleValues" type="boolean" /><attribute name="nearestValue" type="boolean" /><attribute name="current" type="boolean" /></extension></simpleContent></complexType></element><element name="Attribution"><annotation><documentation>
Attribution indicates the provider of a Layer or collection of Layers.
The provider's URL, descriptive title string, and/or logo image URL
may be supplied. Client applications may choose to display one ormore of these items. A format element indicates the MIME type ofthe logo image located at LogoURL. The logo image's width and heightassist client applications in laying out space to display the logo.
</documentation></annotation><complexType><sequence><element ref="wms:Title" minOccurs="0"/><element ref="wms:OnlineResource" minOccurs="0"/><element ref="wms:LogoURL" minOccurs="0"/></sequence></complexType></element><element name="LogoURL"><complexType><sequence><element ref="wms:Format"/><element ref="wms:OnlineResource"/></sequence><attribute name="width" type="positiveInteger"/><attribute name="height" type="positiveInteger"/></complexType></element><element name="MetadataURL"><annotation><documentation>
A Map Server may use zero or more MetadataURL elements to offer
detailed, standardized metadata about the data underneath a
particular layer. The type attribute indicates the standard to which
the metadata complies. The format element indicates how the metadata is structured.
</documentation></annotation><complexType>

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67

OGC 06-042<sequence><element ref="wms:Format"/><element ref="wms:OnlineResource"/></sequence><attribute name="type" type="NMTOKEN" use="required" /></complexType></element><element name="AuthorityURL"><annotation><documentation>
A Map Server may use zero or more Identifier elements to list ID
numbers or labels defined by a particular Authority. For example,
the Global Change Master Directory (gcmd.gsfc.nasa.gov) defines a
DIF_ID label for every dataset. The authority name and explanatory
URL are defined in a separate AuthorityURL element, which may be
defined once and inherited by subsidiary layers. Identifiers
themselves are not inherited.
</documentation></annotation><complexType><sequence><element ref="wms:OnlineResource"/></sequence><attribute name="name" type="NMTOKEN" use="required"/></complexType></element><element name="Identifier"><complexType><simpleContent><extension base="string"><attribute name="authority" type="string" use="required"/></extension></simpleContent></complexType></element><element name="DataURL"><annotation><documentation>
A Map Server may use DataURL offer a link to the underlying data represented
by a particular layer.
</documentation></annotation><complexType><sequence><element ref="wms:Format"/><element ref="wms:OnlineResource"/></sequence></complexType></element><element name="FeatureListURL"><annotation><documentation>
A Map Server may use FeatureListURL to point to a list of thefeatures represented in a Layer.
</documentation></annotation><complexType><sequence><element ref="wms:Format"/><element ref="wms:OnlineResource"/></sequence></complexType></element><element name="Style"><annotation><documentation>

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OGC 06-042

A Style element lists the name by which a style is requested and ahuman-readable title for pick lists, optionally (and ideally)
provides a human-readable description, and optionally gives a style
URL.
</documentation></annotation><complexType><sequence><element ref="wms:Name"/><element ref="wms:Title"/><element ref="wms:Abstract" minOccurs="0"/><element ref="wms:LegendURL" minOccurs="0" maxOccurs="unbounded"/><element ref="wms:StyleSheetURL" minOccurs="0"/><element ref="wms:StyleURL" minOccurs="0"/></sequence></complexType></element><element name="LegendURL"><annotation><documentation>
A Map Server may use zero or more LegendURL elements to provide animage(s) of a legend relevant to each Style of a Layer. The Format
element indicates the MIME type of the legend. Width and height
attributes may be provided to assist client applications in laying out
space to display the legend.
</documentation></annotation><complexType><sequence><element ref="wms:Format"/><element ref="wms:OnlineResource"/></sequence><attribute name="width" type="positiveInteger"/><attribute name="height" type="positiveInteger"/></complexType></element><element name="StyleSheetURL"><annotation><documentation>
StyleSheeetURL provides symbology information for each Style of a Layer.
</documentation></annotation><complexType><sequence><element ref="wms:Format"/><element ref="wms:OnlineResource"/></sequence></complexType></element><element name="StyleURL"><annotation><documentation>
A Map Server may use StyleURL to offer more information about thedata or symbology underlying a particular Style. While the semantics
are not well-defined, as long as the results of an HTTP GET request
against the StyleURL are properly MIME-typed, Viewer Clients andCascading Map Servers can make use of this. A possible use could be
to allow a Map Server to provide legend information.
</documentation></annotation><complexType><sequence><element ref="wms:Format"/><element ref="wms:OnlineResource"/></sequence></complexType></element>

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69

OGC 06-042<element name="MinScaleDenominator" type="double"><annotation><documentation>
Minimum scale denominator for which it is appropriate todisplay this layer.
</documentation></annotation></element><element name="MaxScaleDenominator" type="double"><annotation><documentation>
Maximum scale denominator for which it is appropriate todisplay this layer.
</documentation></annotation></element><!-- ********************************************************************* --><!-- ** Type Definitions.
** --><!-- ********************************************************************* --><simpleType name="longitudeType"><restriction base="double"><minInclusive value="-180" /><maxInclusive value="180" /></restriction></simpleType><simpleType name="latitudeType"><restriction base="double"><minInclusive value="-90" /><maxInclusive value="90" /></restriction></simpleType></schema>

E.2 Service Exception schemaThis annex contains the XML schema for service exception reports and also summarizes the defined exception
codes and their meanings.
The schema may also be found on-line at <http://schemas.opengis.net/wms/1.3.0/>.
Service exception XML shall be valid according to this service exception schema. In an HTTP environment, theMIME type of the returned XML shall be "text/xml". Individual error messages appear as <ServiceException>
elements within the <ServiceExceptionReport> element. The messages can be formatted either as chunks ofplain text or, if included in a character data (CDATA) section, as XML-like text containing angle brackets ("<" and">"), as shown in the example service exception Report in H.2.
The "locator" attribute defined below is an optional string that a server may use to indicate what part(s) of aservice request caused the exception to be generated. The locator is intended to be interpreted by humans rather
than by client software, and as such has no predefined syntax.

<?xml version="1.0" encoding="UTF-8"?><xsd:schema
targetNamespace="http://www.opengis.net/ogc"
xmlns:ogc="http://www.opengis.net/ogc"
xmlns:xsd="http://www.w3.org/2001/XMLSchema"
elementFormDefault="qualified"><xsd:element name="ServiceExceptionReport"><xsd:complexType>70

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OGC 06-042<xsd:sequence><xsd:element name="ServiceException"
type="ogc:ServiceExceptionType"minOccurs="0" maxOccurs="unbounded"/></xsd:sequence><xsd:attribute name="version" type="xsd:string" fixed="1.3.0"/></xsd:complexType></xsd:element><xsd:complexType name="ServiceExceptionType"><xsd:simpleContent><xsd:extension base="xsd:string"><xsd:attribute name="code" type="xsd:string"/><xsd:attribute name="locator" type="xsd:string"/></xsd:extension></xsd:simpleContent></xsd:complexType></xsd:schema>

This International Standard defines several exception codes in Table E.1. Servers shall not use these codes formeanings other than those specified. Clients may use these codes to automate responses to service exceptions.
Table E.1 — Service exception codes
Exception code

Meaning

InvalidFormat

Request contains a Format not offered by the server.

InvalidCRS

Request contains a CRS not offered by the server for one or more of the Layers in therequest.

LayerNotDefined

GetMap request is for a Layer not offered by the server, or GetFeatureInfo request is for aLayer not shown on the map.

StyleNotDefined

Request is for a Layer in a Style not offered by the server.

LayerNotQueryable

GetFeatureInfo request is applied to a Layer which is not declared queryable.

InvalidPoint

GetFeatureInfo request contains invalid I or J value.

CurrentUpdateSequence

Value of (optional) UpdateSequence parameter in GetCapabilities request is equal to current
value of service metadata update sequence number.

InvalidUpdateSequence

Value of (optional) UpdateSequence parameter in GetCapabilities request is greater thancurrent value of service metadata update sequence number.

MissingDimensionValue

Request does not include a sample dimension value, and the server did not declare adefault value for that dimension.

InvalidDimensionValue

Request contains an invalid sample dimension value.

OperationNotSupported

Request is for an optional operation that is not supported by the server.

Copyright © 2006 Open Geospatial Consortium, Inc. All Rights Reserved.

71

OGC 06-042

Annex F(normative)
UML modelThis annex provides Unified Modeling Language (UML) class diagrams for the WMS.
Figure F.1 shows WMS datatypes used in the UML model. Table F.1 maps these classes and their attributes to
WMS service metadata elements and request parameters in the HTTP DCP. Figure F.2 is a class diagram thatsummarizes the WMS interface. The service is composed of a set of operations and a body of data acted upon by
those operations. That data includes both geographic information and metadata about the service. An instance ofthe service is called a server.
The WMS operations are GetCapabilities (see 7.2), GetMap (see 7.3), and GetFeatureInfo (see 7.4); the latter is
optional. Figure F.3 provides a class diagram for each request message. Request messages in the HTTP DCP
are URL query strings as described generally in 6.8 and 6.9, and specifically for each operation in 7.2.3, 7.3.3,
and 7.4.3. Table F.2 shows the mapping of UML request classes to the HTTP DCP request names. Tables F.3,
F.4 and F.5 shows the mapping of the attributes of each UML request class to request parameters in the HTTP
DCP.
Class diagrams for the WMS responses are shown in Figure F.4. The responses are discussed in 7.2.4, 7.3.4,
and 7.4.4.

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OGC 06-042

Figure F.1 — Web Map Service Datatypes

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73

OGC 06-042

Table F.1 — Mapping of UML datatypes to HTTP DCP
UML ClassService Metadata Element

Bounding Box

BoundingBox, CRS

OnlineImage

LegendURL, LogoURL

MIMEtype

FormatRequest Parameter (GetMap
unless otherwise noted)
BBOX, CRS

GetMap response
FORMAT

LayerList

LAYERS

StyleList

STYLES

MapAttributes

BGCOLOR, FORMAT, WIDTH,
HEIGHT, TRANSPARENT

SampleDimension

Dimension

TIME, ELEVATION,
DIM_dimension_name

MapSize

WIDTH, HEIGHT

PixelPoint

I, J (GetFeatureInfo)

URL

Other

OnlineResource, LegendURL, LogoURL

Figure F.2 — Web Map Service interface

74

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OGC 06-042

Figure F.3 — Web map service requests

Table F.2 — Mapping of UML request classes to HTTP DCP
UML class

HTTP request nameMetadataRequest

GetCapabilities

MapRequest

GetMapFeatureInfoRequest

GetFeatureInfo

Table F.3 — Mapping of UML MetadataRequest attributes HTTP GetCapabilities request parameters
UML attribute

HTTP request parameter

FormatFORMAT

OperationName

REQUEST

ServiceSERVICE

UpdateSequence

UPDATESEQUENCE

VersionVERSION

Table F.4 — Mapping of UML MapRequest attributes HTTP GetMap request parameters
UML attribute

HTTP request parameters

BoundingBox

CRS, BBOX

ExceptionFormat

EXCEPTIONS

LayersLAYERS

MapAttributes

BGCOLOR, FORMAT, WIDTH, HEIGHT, TRANSPARENT

OperationName

REQUEST

SampleDimension

TIME, ELEVATION, DIM_dimension_name

StylesSTYLES

VersionVERSION

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OGC 06-042

Table F.5 — Mapping of UML FeatureInfoRequest attributes HTTP GetFeatureInfo request parameters
UML attribute

HTTP request parameters

BoundingBox

CRS, BBOX

ExceptionFormat

EXCEPTIONS

InfoFormat

INFO_FORMAT

LayersLAYERS

MapAttributes

BGCOLOR, FORMAT, WIDTH, HEIGHT, TRANSPARENT

OperationName

REQUEST

point

I, J

queryLayers

QUERY_LAYERS

SampleDimension

TIME, ELEVATION, DIM_dimension_name

StylesSTYLES

VersionVERSION

Figure F.4 — Web Map Service responses

76

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OGC 06-042

Annex G
(informative)
Web Mapping Examples

This annex provides some illustrative URLs and their resulting maps.

G.1 Example 1: One Server, One Layer, Default Style
The following hypothetical URL requests the US National Oceanographic and Atmospheric Administration
hurricane image shown in Figure G.1:
http://a-map-co.com/mapserver.cgi?VERSION=1.3.0&REQUEST=GetMap&
CRS=CRS:84&BBOX=-97.105,24.913,-78.794,36.358&
WIDTH=560&HEIGHT=350&LAYERS=AVHRR-09-27&STYLES=&FORMAT=image/png&EXCEPTIONS=INIMAGE

Figure G.1 — NOAA hurricane image of the Gulf of Mexico

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OGC 06-042

G.2 Example 2: One Server, Three Layers, Named Styles
The following hypothetical URL requests three layers — built-up areas, coastlines, and political boundaries — toproduce the map shown in Figure G.2. A transparent background has been requested for the map.
http://b-maps.com/map.cgi?VERSION=1.3.0&REQUEST=GetMap&
CRS=CRS:84&BBOX=-97.105,24.913,-78.794,36.358&
WIDTH=560&HEIGHT=350&LAYERS=BUILTUPA_1M,COASTL_1M,POLBNDL_1M&
STYLES=0XFF8080,0X101040,BLACK&FORMAT=image/png&BGCOLOR=0xFFFFFF&
TRANSPARENT=TRUE&EXCEPTIONS=INIMAGE

Figure G.2 — Political, coastline, and populated areas, Southeastern United States
Notice that in both of these URLs the map projection information is identical:
CRS=CRS:84&BBOX=-97.105,24.913,-78.794,36.358&WIDTH=560&HEIGHT=350.
The second map, for which a transparent background was requested (TRANSPARENT=TRUE), can therefore be
precisely overlaid on the first.

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OGC 06-042

G.3 Example 3: Two Servers, Four Layers
Figure G.3 shows the result of overlaying Figure G.1 on Figure G.2 to produce a composite map from two
separate servers.

Figure G.3 — Combined hurricane image and population map

Copyright © 2006 Open Geospatial Consortium, Inc. All Rights Reserved.

79OGC 06-042

Annex H(informative)
XML examples

H.1 Sample WMS service metadata
As an aid to understanding and a guide for implementation, this annex contains example XML which is valid
according to the schema in E.1. Implementers should consult the main body of this International Standard and theschema to ensure compliance rather than editing this XML without full understanding, as the examples herein
apply only to a limited range of cases.
This example XML may also be found online at <http://schemas.opengis.net/wms/1.3.0/>.
<?xml version='1.0' encoding="UTF-8"?><WMS_Capabilities version="1.3.0" xmlns="http://www.opengis.net/wms"
xmlns:xlink="http://www.w3.org/1999/xlink"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.opengis.net/wms
http://schemas.opengis.net/wms/1.3.0/capabilities_1_2_0.xsd"><!-- Service Metadata --><Service><!-- The WMT-defined name for this type of service --><Name>WMS</Name><!-- Human-readable title for pick lists --><Title>Acme Corp. Map Server</Title><!-- Narrative description providing additional information --><Abstract>Map Server maintained by Acme Corporation.
Contact: webmaster@wmt.acme.com.
maps showing roadrunner nests and possible ambush locations.</Abstract><KeywordList><Keyword>bird</Keyword><Keyword>roadrunner</Keyword><Keyword>ambush</Keyword></KeywordList><!-- Top-level web address of service or service provider. See also OnlineResource
elements under <DCPType>. --><OnlineResource xmlns:xlink="http://www.w3.org/1999/xlink" xlink:type="simple"
xlink:href="http://hostname/" /><!-- Contact information --><ContactInformation><ContactPersonPrimary><ContactPerson>Jeff Smith</ContactPerson><ContactOrganization>NASA</ContactOrganization></ContactPersonPrimary><ContactPosition>Computer Scientist</ContactPosition><ContactAddress><AddressType>postal</AddressType><Address>NASA Goddard Space Flight Center</Address><City>Greenbelt</City><StateOrProvince>MD</StateOrProvince><PostCode>20771</PostCode><Country>USA</Country></ContactAddress><ContactVoiceTelephone>+1 301 555-1212</ContactVoiceTelephone><ContactElectronicMailAddress>user@host.com</ContactElectronicMailAddress></ContactInformation><!-- Fees or access constraints imposed. --><Fees>none</Fees><AccessConstraints>none</AccessConstraints><LayerLimit>16</LayerLimit>

80

High-quality

Copyright © 2006 Open Geospatial Consortium, Inc. All Rights Reserved.

OGC 06-042<MaxWidth>2048</MaxWidth><MaxHeight>2048</MaxHeight></Service><Capability><Request><GetCapabilities><Format>text/xml</Format><DCPType><HTTP><Get><OnlineResource xmlns:xlink="http://www.w3.org/1999/xlink"
xlink:type="simple"
xlink:href="http://hostname/path?" /></Get><Post><OnlineResource xmlns:xlink="http://www.w3.org/1999/xlink"
xlink:type="simple"
xlink:href="http://hostname/path?" /></Post></HTTP></DCPType></GetCapabilities><GetMap><Format>image/gif</Format><Format>image/png</Format><Format>image/jpeg</Format><DCPType><HTTP><Get><!-- The URL here for invoking GetCapabilities using HTTP GET
is only a prefix to which a query string is appended. --><OnlineResource xmlns:xlink="http://www.w3.org/1999/xlink"
xlink:type="simple"
xlink:href="http://hostname/path?" /></Get></HTTP></DCPType></GetMap><GetFeatureInfo><Format>text/xml</Format><Format>text/plain</Format><Format>text/html</Format><DCPType><HTTP><Get><OnlineResource xmlns:xlink="http://www.w3.org/1999/xlink"
xlink:type="simple"
xlink:href="http://hostname/path?" /></Get></HTTP></DCPType></GetFeatureInfo></Request><Exception><Format>XML</Format><Format>INIMAGE</Format><Format>BLANK</Format></Exception><Layer><Title>Acme Corp. Map Server</Title><CRS>CRS:84</CRS> <!-- all layers are available in at least this CRS --><AuthorityURL name="DIF_ID"><OnlineResource xmlns:xlink="http://www.w3.org/1999/xlink" xlink:type="simple"
xlink:href="http://gcmd.gsfc.nasa.gov/difguide/whatisadif.html" /></AuthorityURL><Layer><!-- This parent layer has a Name and can therefore be requested from a Map Server, yielding a mapof all subsidiary layers. --><Name>ROADS_RIVERS</Name><Title>Roads and Rivers</Title><!-- See the spec to learn how some characteristics are inherited by

Copyright © 2006 Open Geospatial Consortium, Inc. All Rights Reserved.

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OGC 06-042

subsidiary layers. --><CRS>EPSG:26986</CRS> <!-- An additional CRS for this layer --><EX_GeographicBoundingBox><westBoundLongitude>-71.63</westBoundLongitude><eastBoundLongitude>-70.78</eastBoundLongitude><southBoundLatitude>41.75</southBoundLatitude><northBoundLatitude>42.90</northBoundLatitude></EX_GeographicBoundingBox><!-- The optional resx and resy attributes indicate the X and Y spatial
resolution in the units of that CRS. --><BoundingBox CRS="CRS:84"
minx="-71.63" miny="41.75" maxx="-70.78" maxy="42.90" resx="0.01" resy="0.01"/><BoundingBox CRS="EPSG:26986"
minx="189000" miny="834000" maxx="285000" maxy="962000" resx="1" resy="1" /><!-- Optional Title, URL and logo image of data provider. --><Attribution><Title>State College University</Title><OnlineResource xmlns:xlink="http://www.w3.org/1999/xlink" xlink:type="simple"
xlink:href="http://www.university.edu/" /><LogoURL width="100" height="100"><Format>image/gif</Format><OnlineResource xmlns:xlink="http://www.w3.org/1999/xlink"
xlink:type="simple"
xlink:href="http://www.university.edu/icons/logo.gif" /></LogoURL></Attribution><!-- Identifier whose meaning is defined in an AuthorityURL element --><Identifier authority="DIF_ID">123456</Identifier><FeatureListURL><Format>XML"</Format><OnlineResource xmlns:xlink="http://www.w3.org/1999/xlink" xlink:type="simple"
xlink:href="http://www.university.edu/data/roads_rivers.gml" /></FeatureListURL><Style><Name>USGS</Name><Title>USGS Topo Map Style</Title><Abstract>Features are shown in a style like that used in USGS topographic maps.</Abstract><!-- A picture of a legend for a Layer in this Style --><LegendURL width="72" height="72"><Format>image/gif</Format><OnlineResource xmlns:xlink="http://www.w3.org/1999/xlink"
xlink:type="simple"
xlink:href="http://www.university.edu/legends/usgs.gif" /></LegendURL><!-- An XSL stylesheet describing how feature data will rendered to createa map of this layer. --><StyleSheetURL><Format>text/xsl</Format><OnlineResource xmlns:xlink="http://www.w3.org/1999/xlink"
xlink:type="simple"
xlink:href="http://www.university.edu/stylesheets/usgs.xsl" /></StyleSheetURL></Style><Layer queryable="1"><Name>ROADS_1M</Name><Title>Roads at 1:1M scale</Title><Abstract>Roads at a scale of 1 to 1 million.</Abstract><KeywordList><Keyword>road</Keyword><Keyword>transportation</Keyword><Keyword>atlas</Keyword></KeywordList><Identifier authority="DIF_ID">123456</Identifier><MetadataURL type="FGDC:1998"><Format>text/plain</Format><OnlineResource xmlns:xlink="http://www.w3.org/1999/xlink"
xlink:type="simple"
xlink:href="http://www.university.edu/metadata/roads.txt" /></MetadataURL><MetadataURL type="ISO19115:2003"><Format>text/xml</Format>

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OGC 06-042<OnlineResource xmlns:xlink="http://www.w3.org/1999/xlink"
xlink:type="simple"
xlink:href="http://www.university.edu/metadata/roads.xml" /></MetadataURL><!-- In addition to the Style specified in the parent Layer, this Layer isavailable in this style. --><Style><Name>ATLAS</Name><Title>Road atlas style</Title><Abstract>Roads are shown in a style like that used in a commercial road atlas.</Abstract><LegendURL width="72" height="72"><Format>image/gif</Format><OnlineResource xmlns:xlink="http://www.w3.org/1999/xlink"
xlink:type="simple"
xlink:href="http://www.university.edu/legends/atlas.gif" /></LegendURL></Style></Layer><Layer queryable="1"><Name>RIVERS_1M</Name><Title>Rivers at 1:1M scale</Title><Abstract>Rivers at a scale of 1 to 1 million.</Abstract><KeywordList><Keyword>river</Keyword><Keyword>canal</Keyword><Keyword>waterway</Keyword></KeywordList></Layer></Layer><Layer queryable="1"><Title>Weather Forecast Data</Title><CRS>CRS:84</CRS> <!-- harmless repetition of common CRS --><EX_GeographicBoundingBox><westBoundLongitude>-180</westBoundLongitude><eastBoundLongitude>180</eastBoundLongitude><southBoundLatitude>-90</southBoundLatitude><northBoundLatitude>90</northBoundLatitude></EX_GeographicBoundingBox><!-- These weather data are available daily from 1999-01-01 through2000-08-22. --><Dimension name="time" units="ISO8601" default="2000-08-22">
1999-01-01/2000-08-22/P1D</Dimension><Layer><Name>Clouds</Name><Title>Forecast cloud cover</Title></Layer><Layer><Name>Temperature</Name><Title>Forecast temperature</Title></Layer><Layer><Name>Pressure</Name><Title>Forecast barometric pressure</Title><!-- This Pressure layer is available at several elevations and times. --><Dimension name="elevation" units="EPSG:5030" /><Dimension name="time" units="ISO8601" default="2000-08-22">
1999-01-01/2000-08-22/P1D</Dimension><Dimension name="elevation" units="CRS:88" default="0" nearestValue="1">0,1000,3000,5000,10000</Dimension></Layer></Layer><!-- Example of a layer which is a static map of fixed
size which the server cannot subset or make transparent --><Layer opaque="1" noSubsets="1" fixedWidth="512" fixedHeight="256"><Name>ozone_image</Name><Title>Global ozone distribution (1992)</Title><EX_GeographicBoundingBox><westBoundLongitude>-180</westBoundLongitude><eastBoundLongitude>180</eastBoundLongitude>

Copyright © 2006 Open Geospatial Consortium, Inc. All Rights Reserved.

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OGC 06-042<southBoundLatitude>-90</southBoundLatitude><northBoundLatitude>90</northBoundLatitude></EX_GeographicBoundingBox><Dimension name="time" units="ISO8601" default="1992">1992</Dimension></Layer><!-- Example of a layer which originated from another WMS and has been"cascaded" by this WMS. --><Layer cascaded="1"><Name>population</Name><Title>World population, annual</Title><EX_GeographicBoundingBox><westBoundLongitude>-180</westBoundLongitude><eastBoundLongitude>180</eastBoundLongitude><southBoundLatitude>-90</southBoundLatitude><northBoundLatitude>90</northBoundLatitude></EX_GeographicBoundingBox><Dimension name="time" units="ISO8601" default="2000">1990/2000/P1Y</Dimension></Layer></Layer></Capability></WMS_Capabilities>

H.2 Sample service exception XML
As an aid to understanding and a guide for implementation, this Annex contains example XML which is valid
according to the schema in E.2.
This example XML may also be found online at <http://schemas.opengis.net/wms/1.3.0/>.
<?xml version='1.0' encoding="UTF-8"?><ServiceExceptionReport version="1.3.0"
xmlns="http://www.opengis.net/ogc"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.opengis.net/ogc
http://schemas.opengis.net/wms/1.3.0/exceptions_1_3_0.xsd"><ServiceException>
Plain text message about an error.
</ServiceException><ServiceException code="InvalidUpdateSequence">
Another error message, this one with a service exception code supplied.
</ServiceException><ServiceException><![CDATA[
Error in module <foo.c>, line 42
A message that includes angle brackets in text
must be enclosed in a Character Data Section
as in this example. All XML-like markup isignored except for this sequence of threeclosing characters:]]></ServiceException><ServiceException><![CDATA[<Module>foo.c</Module><Error>An error occurred</Error><Explanation>Similarly, actual XML
can be enclosed in a CDATA section.
A generic parser will ignore that XML,but application-specific software may choose
to process it.</Explanation>]]></ServiceException></ServiceExceptionReport>

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Copyright © 2006 Open Geospatial Consortium, Inc. All Rights Reserved.

OGC 06-042

Bibliography[1]

FGDC-STD-001-1998, Content Standard for Digital Geospatial Metadata (version 2), US Federal
Geographic Data Committee. Available at: <http://www.fgdc.gov/metadata/contstan.html>[2]Internet Assigned Numbers Authority, MIME
<http://www.iana.org/assignments/media-types/>[3]

ISO 19117:2005, Geographic information — Portrayal[4]

ISO 19119:2005, Geographic information — Services[5]

ISO 19125-1:2004, Geographic information — Simple feature access — Part 1: Common architecture[6]

LALONDE, W. (ed.), Styled Layer Descriptor Implementation Specification 1.0.0, OGC Document #02-070,
August 2002. Available at <http://www.opengis.org/techno/specs/>[7]

VRETANOS, P. (ed.), Web Feature Service Implementation Specification 1.0.0, OGC Document #02-058,
September 2003. Available from World Wide Web: <http://www.opengis.org/techno/specs/>[8]

XML Schema (May 2001), XML Schema Part 2: Datatypes, World Wide Web Consortium
Recommendation, Biron, P. and Malhotra, A., eds., Available at <http://www.w3.org/TR/>[9]

ISO 6709:1983, Standard representation of latitude, longitude and altitude for geographic point locations[10]

ISO/IEC 8632 (all parts), Information technology — Computer graphics — Metafile for the storage andtransfer of picture description information[11]

ISO/IEC TR 14252:1996, Information technology — Guide to the POSIX Open System Environment(OSE)

Copyright © 2006 Open Geospatial Consortium, Inc. All Rights Reserved.

Media

Types.

from

World

Wide

Web:

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