current direction is identical to direction on the screen. For other map projections, the portrayed direction must be computed. Figure 9.3 – Portrayal of the arrow’s direction, based on the current direction. The dashed line is the arrow’s centerline, and the origin of the East-North axis is at the arrow’s pivot point. True north has a direction of 0 degrees. 9.2.3 Arrow Colour and Speed Bands The colour of the arrow must be based on the speed value of the data, and must have 9 bands corresponding to the speed ranges (Table 9.1). The range of speeds (Table 9.1) was selected to (a) emphasize differences at low speeds (0.0 to 3 kn), and (b) be capable of displaying large currents (13 kn and above). NOTE: The largest tidal currents may be those in the strait near Saltstrumen, Norway, which reach 22 kn. Table 9.1 – Speed ranges (knots) for the 9-band display. Speed Band Minimum Speed (kn) Maximum Speed (kn) Appx. Interval (kn) 1 0.00 0.49 0.5 2 0.50 0.99 0.5 3 1.00 1.99 1 4 2.00 2.99 1 5 3.00 4.99 2 6 5.00 6.99 2 7 7.00 9.99 3 8 10.00 12.99 3 9 13.00 99.99 87 Colours are associated with each speed band, and must be distinguishable in the three viewing environments: day, dusk, and night. Color values for day conditions are shown in Table 9.2. Colours for dusk and night conditions are given in ANNEX H – COLOUR TABLES. (The monitor gamma values need to be taken into account – refer to IHO standards). Table 9.2 – Colour schema for day conditions.
12.2.2 S100_CatalogueIdentifier Role Name Name Description Mult Type Remarks Class S100_CatalogueIdentifier An exchange catalogue contains the discovery metadata about the exchange datasets and support files - - - Attribute identifier Uniquely identifies this exchange catalogue 1 CharacterString Attribute editionNumber The edition number of this exchange catalogue 1 CharacterString Attribute date Creation date of the exchange catalogue 1 Date 12.2.3 S100_CataloguePointofContact Role Name Name Description Mult Type Remarks Class S100_CataloguePointOfContact Contact details of the issuer of this exchange catalogue - - - Attribute organization The organization distributing this exchange catalogue 1 CharacterString This could be an individual producer, value added reseller, etc. Attribute phone The phone number of the organization 0..1 CI_Telephone Attribute address The address of the organization 0..1 CI_Address
12.2.4 S100_DatasetDiscoveryMetaData Data in the Discovery Metadata are used to identify the relevance of the dataset to the particular application. Name Description Mult Value Type Remarks S100_DatasetDiscoveryMetadata Metadata about the individual datasets in the exchange catalogue - - - fileName Dataset file name 1 CharacterString filePath Full path from the exchange set root directory 1 CharacterString Path relative to the root directory of the exchange set. The location of the file after the exchange set is unpacked into directory <EXCH_ROOT> will be <EXCH_ROOT>/<filePath>/<filename> description Short description giving the area or location covered by the dataset 1 CharacterString E.g. a harbour or port name, between two named locations etc. dataProtection Indicates if the data is encrypted 0..1 Boolean 0 indicates an unencrypted dataset 1 indicates an encrypted dataset protectionScheme specification or method used for data protection 0..1 CharacterString Eg S-63 digitalSignature Indicates if the data has a digital signature 0..1 Boolean 0: unsigned 1: datafile is digitally signed [to be reconciled when S-100 finalizes digital signature elements] digitalSignatureValue Digital signature 0..1 CharacterString This contains a base64 encoding of the hexadecimal numbers comprising the digital signature itself. The content of these fields are defined, along with the algorithms for their calculation, in S-63 ed2.0 Part (C). [to be reconciled when S-100 finalizes digital signature elements] classification Indicates the security classification of the dataset 0..1 Enumeration One of the following from ISO 19115 (codelist) 1. unclassified 2. restricted 3. confidential 4. secret 5. top secret purpose The purpose for which the dataset has been issued 1 CharacterString E.g. new, re-issue, new edition, update etc. specificUsage The use for which the dataset is intended 1 CharacterString E.g. in the case of ENCs this would be a navigation purpose classification.
12.2.5.1 EX_GeographicBoundingBox From ISO 19115:2003 Corr. 1 (2006). Name Description Mult Type Remarks geographic position of the dataset - - Defined in ISO 19115 westBoundLongitude western-most coordinate of the limit of the dataset extent, expressed in longitude in decimal degrees (positive east) 1 Real Arc degrees eastBoundLongitude eastern-most coordinate of the limit of the dataset extent, expressed in longitude in decimal degrees (positive east) 1 Real Arc degrees southBoundLatitude southern-most coordinate of the limit of the dataset extent, expressed in latitude in decimal degrees (positive north) 1 Real Arc degrees northBoundLatitude northern-most, coordinate of the limit of the dataset extent expressed in latitude in decimal degrees (positive north) 1 Real Arc degrees 12.1.5.2 EX_BoundingPolygon From ISO 19115:2003 Corr. 1 (2006). Name Description Mult Type Remarks EX_BoundingPolygon boundary enclosing the dataset, expressed as the closed set of (x,y) coordinates of the polygon (last point replicates first point) - - Defined in ISO 19115 polygon sets of points defining the bounding polygon 1 GM_Object Must be a GM_Polygon (See S-100 Part 7, ISO 19107, ISO 19136)
12.2.7 S111_DataFormat Role Name Name Description Mult Type Remarks Class S100_DataFormat Encoding format - - Value HDF5 Format 1 Character 12.2.8 S100_ProductSpecification Name Description Mult Type Remarks S100_ProductSpecification The Product Specification contains the information needed to build the specified product - - - name The name of the product specification used to create the datasets 1 CharacterString S-111 Surface Current Product Specification version The version number of the product specification 1 CharacterString 1.0.0 date The version date of the product specification 1 Date 12.2.9 S100_CatalogueMetadata Identifies components of the Catalogue. Name Description Mult Value Type Remarks S100_CatalogueMetadata - - - filename The name for the catalogue 1..* CharacterString fileLocation Full location from the exchange set root directory 1..* CharacterString Path relative to the root directory of the exchange set. The location of the file after the exchange set is unpacked into directory <EXCH_ROOT> will be <EXCH_ROOT>/<filePath>/<filename> scope Subject domain of the catalogue 1..* S111_CatalogueScope versionNumber The version number of the product specification 1..* CharacterString issueDate The version date of the product specification 1..* Date productSpecification The product specification used to create this file 1..* S100_ProductSpecification digitalSignatureReference Digital Signature of the file 1 CharacterString Reference to the appropriate digital signature algorithm digitalSignatureValue Value derived from the digital signature 1 CharacterString
set unordered collection of related items (objects or values) with no repetition [ISO 19107] specification declarative description of what something is or does NOTE: Contrast: implementation [retired version of ISO/TS 19103] timestamp value of time at which an object’s state is measured and recorded [ISO 19132] symbol portrayal primitive that can be graphic, audible, or tactile in nature, or a combination of these [ISO 19117] tuple ordered list of values NOTE 1: The number of values in a tuple is immutable NOTE 2: the ordered list will generally be a finite sequence of features, each of a specific feature type [ISO 19136, ISO 19142] type a specification of the general structure and behavior of a domain of objects without providing a physical implementation NOTE: A type may have attributes and associations [ISO/TS 19103] UML The Unified Modeling Language (UML) is a in the field of , which is designed to provide a standard way to visualize the design of a system. image courtesy of [Wikipedia 2015] UML application schema application schema written in UML in accordance with ISO 19109 [ISO 19136]valid time time when a fact is true in the abstracted reality [ISO 19108] vector quantity having direction as well as magnitude NOTE: A directed line segment represents a vector if the length and direction of the line segment are equal to the magnitude and direction of the vector. The term vector data refers to data that represents the spatial configuration of features as a set of directed line segments [ISO 19123] vertical coordinate system one-dimensional coordinate system used for height or depth measurements [ISO 19111] vertical datum datum describing the relation of gravity-related heights or depths to the Earth NOTE: In most cases the vertical datum will be related to mean sea level. Ellipsoidal heights are treated as related to a three-dimensional ellipsoidal coordinate system referenced to a geodetic datum. Vertical datums include sounding datums (used for hydrographic purposes), in which case the heights may be negative heights or depths [ISO 19111]
E.2.4 Temporal Accuracy For a gridded coverage the temporal reference time for the data at all grid points is the same. Temporal accuracy is not defined. ANNEX F. SURFACE CURRENT DATA This Annex describes the sources of data, methods of organizing surface current data (the time series and the grid), how the data product format is derived. In the last section we discuss additional features of current data. F.1 Data Sources For the purposes of this Product Specification, surface current data categorized as one of three types, depending on the source of production. These are: Historical and real-time observation, Astronomical prediction, and Model-based forecast or prediction. An historical observation consists of a time series of values at a specific location or area, often at a specific elevation above the bottom or below the surface. Observations can be for a fixed point (current meter), a moving point (e.g., a Lagrangian drifter), along a vertical or horizontal line (Doppler profiler), or an area (coastal radar). A real-time (or near-real-time) observation is actually a historical observation but for the very recent past. The astronomical tidal current prediction is often a time series computed by a mathematical formula using harmonic constants. This prediction applies to a specific location and depth, and is often produced many months ahead of time. The astronomical predictions for multiple stations are often combined into a digital tidal atlas, and the individual predicted currents are usually keyed to the time and amplitude of tidal water levels at a nearby station. Finally, model-based forecasts or predictions are usually produced by a two- or numerical hydrodynamic model, and include astronomical tide, meteorological forcing, river inflow, spatially varying water density, and open ocean boundary inputs. A hindcast, including an analysis, is based on historically-observed conditions. A forecast is usually produced to predict conditions a few hours or days ahead into the future. F.2 Data Organization Data are usually organized by the HO producer into either (a) a time series of values, such as for historical and real-time observations at a single point, or (b) a gridded set of values, such as from a model-based forecast or sea-surface analysis.