**Session No. 4**

### Session Title: Spatial Analysis: Application Tools for Vulnerability Analysis 

**Time:** Three Hours

**Objectives:**

At the conclusion of this session, students should be able to:

> 4.1 Explain the concept "geographic information system" (GIS) and its
> elements.

-   Clarify how a GIS differs from an "information system."

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-   Using the elements of a "system," illustrate the components of a
    GIS.

4.  4.2 Define "geographic spatial object classes" (line, point, and
    polygon)

-   Explain and illustrate vector

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-   Explain longitude and latitude

> 4.3 Explain the nature of "Tiger Files"

4.4 Explain and illustrate image data sources or types

4.5 Explain the nature and purpose of geo-coding

6.  Explain the nature and use of global positioning systems

> 4.7 Using the Q3 FIRM case study, explain how this data could be used
> in a vulnerability analysis and identify critical issues that must be
> addressed by emergency managers in using GIS.

**Scope:** This session will explain the nature of geographic
information systems (GIS) and their application to vulnerability
analysis. Elements of a GIS will be outlined and uses of GIS in
emergency management will be examined.

**Readings:**

**Instructor**

Herring, Thomas A. "The Global Positioning System," *Scientific
American*. Feb 1996. Pp 44--50.

Ross T. Newkirk. "Extending Geographic Information Systems for Risk
Analysis and Management," *Journal of Contingencies and Crisis
Management.* Vol. 1 #4, Dec. 1993.

State University of New York at Buffalo and GIS Resource Group, Inc. New
York State Archives and Records Administration, National Center for
Geographical Information and Analysis. *Helping Local Government Create
a GIS.* 1997. (Volumes 1,2, & 3).

[www.geog.buffalo.edu/ncgia/sara](http://www.geog.buffalo.edu/ncgia/sara)
(Volume 2 and 3 are suggested as references. See Readings: 4-Volume1.prf
for a copy of this document. Volumes 2 and 3 are also available.)

U.S. Flood Insurance Administration, FEMA. "FEMA Flood Insurance Rate
Maps Case Study," adapted from *Users Guide to the Q3 Digital Flood
Insurance Rate Maps*, Washington, DC 1996. (See Readings: 4-Q3Case---A
Word Document.)

**Student**

Herring, Thomas A. "The Global Positioning System," *Scientific
American*. Feb 1996. Pp 44--50.

State University of New York at Buffalo and GIS Resource Group, Inc. New
York State Archives and Records Administration, National Center for
Geographical Information and Analysis. *Helping Local Government Create
a GIS.* 1997. (Volumes 1,2, & 3).

[www.geog.buffalo.edu/ncgia/sara](http://www.geog.buffalo.edu/ncgia/sara)
(Volume 2 and 3 are suggested as references. See Readings: 4-Volume1.prf
for a copy of this document. Volumes 2 and 3 are also available.)

U.S. Flood Insurance Administration, FEMA "FEMA Flood Insurance Rate
Maps Case Study," Adapted from *Users Guide to the Q3 Digital Flood
Insurance Rate Maps*., Washington, DC 1996. (See Readings: 4-Q3Case---a
Word document.)

**References**

##### Adventure GPS Products, "Buyer's Guide to GPS Receiver Features," Lancaster, CA. [**http://www.gps4fun.com/how-to-use.html**](http://www.gps4fun.com/how-to-use.html).

Antenucci, John C., et. al., *Geographic Information Systems: A Guide to
the Technology,* New York: Van Nostrand Reinhold, 1991.

Aronoff, S., 1991 *Geographic Information Systems: A Management
Perspective.* Ottawa: WDL Pub., p.194.

Berry, J.K., 1995, "Raster is Faster, But Vector is Corrector," *GIS
World*, 8(6):35-35.

Birkin, Mark; Clarke, Graham; Clarke, Martin; Wilson, Alan. *Intelligent
GIS: Location Decisions and Strategic Planning.* John Wiley & Sons: New
York, 1996.

Carrara, Alberto and Fausto Guzzetti, Editors. *Geographic Information
Systems in Assessing Natural Hazards.* Kluwer Academic Publishers Group:
Hingham, MA 360. 1995.

Dana, Peter H. "Global Positioning System Overview." The Geographer's
Craft Project. Department of Geography, University of Texas. Download
from <http://www.utexas.edu/depts/grg/gcraft/notes/gps/gps.html>.

Dana, Peter H. "Map Projection Overview" The Geographer's Craft Project.
Department of Geography, University of Texas. Download from
<http://www.utexas.edu/depts/grg/gcraft/notes/gps/gps.html>.

ESRI, 1992b, *Understanding GIS*, Redlands, CA: Environmental Systems
Research Institute, Inc., p. 598.

Greenway, A. Roger. *Risk Management Planning Handbook: A Comprehensive
Guide to Hazard Assessment, Accidental Release Prevention and
Consequence Analysis.* Rockville: Government Institutes, Inc. 1998.

Jarman, Alan M.G. "Smart Spatial Information Systems: Extending
Geographic Information Systems in the Space Age." Journal of
Contingencies and Crisis Management. Vol. 1 #4. Pp. 229-240. December
1993.

Johnson, Glenn O. "GIS Applications in Emergency Management," *URISA
Journal.* 4 (Spring 1992) 66 -- 72.

Korte, George B., *A Practioner's Guide: The GIS book*, Sante Fe: On
Word Press, 1992.

New York State Archives and Records Administration National Center for
Geographical Information and Analysis, State University of New York at
Buffalo and GIS Resource Group, Inc. *Helping Local Government Create a
GIS (Volumes 1,2, & 3),* 1997.

[www.geog.buffalo.edu/ncgia/sara](http://www.geog.buffalo.edu/ncgia/sara)
(Volume 1 is required reading)

> Volume 2: Survey of Available Data, Evaluating Hardware and Software,
> Database Planning and Design, Database Construction and Pilot Studies
> and Benchmark Tests
>
> Volume 3: Acquisition of GIS Hardware and Software, GIS System
> Integration, GIS Application Development, GIS Use and Maintenance

Ross T. Newkirk. "Extending Geographic Information Systems for Risk
Analysis and Management," *Journal of Contingencies and Crisis
Management.* Vol. 1 #4, Dec. 1993.

Srinivas, Emani, "Applications in Hazard Assessment and Management."
Explorations in Geographic Information Systems Technology. V. 6. Geneva,
Switzerland: United Nations Institute for Training and Research 1996.
(includes 3 computer disks, 3 ½\").

Tzemos, S., R.A. Burnett. Use of GIS in the Federal Emergency Management
Informatin System (FEMIS). See:
<http://www.esri.com/base/common/userconf/proc95/to350/p345.html>.

##### 

##### Remarks:

> **Question for the Class:** Geographic Information Systems: How does
> it fit into the emergency management system?
>
> *Geographic information systems, including their programs, data, maps,
> charts, and tables are used as a resource in decision making
> throughout the emergency management process. From planning decisions
> on the locations of shelters, decisions in a response concerning the
> best evacuation route, mitigation decisions relating to the extent of
> flooding, or decisions in recovery clarifying the total damage to
> homes in a tornado, GIS is a tool for providing needed information.*

**4.1 Geographic Information System: A Review of the Technology**

*Geographic information* is information which relates to specific
locations. It involves the physical environment with data associated
with it. A *geographic information system* is an organized collection of
computer hardware and software designed to efficiently create,
manipulate, analyze, and display all types of geographical or spatial
data. A GIS allows complex spatial operations that are very difficult to
do otherwise.

The term *geographic* describes data that is related to geographic
scales of measurement and corresponds by some coordinate system to
locations on the surface of the earth. Other types of information
systems may contain details about location, but in a GIS, spatial
objects and their locations are the very building blocks of the system.

It is possible to use GIS to ask questions of the geographic database,
obtaining "information" about the geography world. This entails the
extraction of specific and meaningful information from a diverse
collection of data, and it is possible only because of the way in which
the data are organized into a "model" of the real world.

The geographic information "system" involves the environment and allows
data to be managed in association with geographic references and
questions to be posed. In the most general sense, a GIS need not be
automated (for example a traditional roadmap), but should be an
integrated set of procedures for the input, storage, manipulation and
output of geographic information. Such a system is most readily achieved
by automated means.

A geographic information system (GIS) is thus a data handling and
analysis system based on sets of data distributed spatially in two
dimensions. It is a geo-based or geo-coded information system. It is an
information system, but one in which the data relates to a geographical
location. Thus a GIS would not only have a means of creating and editing
lists and tables of schools, hospitals, nursing homes, or shelters but
also have the capability of displaying this data in a graphic or map
format.

The data sets may be map oriented, when they comprise qualitative
attributes of an area recorded as lines, points, and areas (polygons).
Lines, points, and polygons are used in a Vector format. A second type
of format is image oriented; the data in this format has quantitative
attributes referring to cells in a rectangular grid.

***A Manager's Concern***

The "Manager's Overview" suggests that "GIS development is a process of
technological innovation and requires management attention appropriate
to this type of activity (p.2). It should be active as opposed to
passive management involvement in the project. Failures of GIS in the
past resulted not from technical difficulties but from a "lack of
realistic expectations of all parties associated with the project,
including GIS technicians, potential users, managers, and officials. The
"Manager's Overview" suggests that the emergency manager get involved in
planning for the development of a GIS. The emergency manager may be in a
position to facilitate realistic expectations from technical staff,
users, and other support staff who might assist in the development of
GIS data.

> **Question for the Class:** For an emergency manager, how could
> geographically based data be useful in emergency management? What
> types of data could be used? How?
>
> *Maps provide a very visual presentation of an event, phenomenon, or
> idea. For emergency managers, being able to see the area affected by a
> disaster supports communication and decision making. An area affected
> by a flood or a chemical spill can be shown on a map along with other
> information such as the location of critical facilities including
> schools, hospitals, nursing homes, schools, parks, shopping areas,
> business areas, manufacturing areas, and transportation routes. Seeing
> the location of critical facilities in an area affected by an
> emergency could help emergency managers in determining appropriate
> evacuation routes or shelter locations.*
>
> *Having the precise location of a school, hospital, park, or business
> is useful, but other information associated with these sites would
> enhance the manager's decision making. Knowing the school enrollment,
> the number of beds at a hospital by type, or the type of patients in a
> nursing home could provide the emergency manager with timely
> information for use in making evacuation decisions. This type of
> information can be part of a geographic information system and
> available to the emergency manager.*

***Application of GIS***

A GIS is a system that includes data, graphics, and a program to
munipulate both the data and the graphics. As a system it includes the
basic characteristics of all systems. GIS involves the following
capabilities to manipulate geo-referenced spatial data:

1.  Input (encoding) (collection of phone listings, census information
    by geographic area---block groups or tracks)

2.  Data management (storage and retrieval) and analysis (GIS systems
    such as ArcView, MapInfo, Geo-Media, LandView/Marplot)

3.  Output (maps showing risk zones, vulnerable population, phone
    listings in vulnerable areas.)

The GIS stores, retrieves, manipulates, analyzes and displays these data
according to user-defined specifications. Ideally the GIS is used as a
decision support system involving the integration of spatially
referenced data in a problem solving environment.

Risk analysis occurs in emergency management from two perspectives
including ex ante (prior to the event) and ex post facto (after the
event). Newkirk (1993) sees that a geographic information system
provides critical views of potential disasters and their impact both
prior to an event and in the post event analysis. He is afraid that the
commercial GIS might encourage the user to assume that the data is
exact. The system should be used to allow for a broader examination of
the risks and their potential or actual (as calculated) impact. There is
a need for the broad-based emergency management community to have a risk
assessment tool that allows for close examination of events and their
outcomes.

*Benefits of a GIS to the Emergency Manager*

Benefits center on providing information to enhance decision making
associated with emergency planning, response, recovery, and mitigation
efforts.

-   A GIS can provide regular maps of the local community and of areas
    of special interest to emergency management.

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-   A GIS can conduct spatial queries and display the results. Such
    queries could include: what residents are within a 100 year flood
    zone; which schools or nursing homes are within 300 yards of a rail
    line or major state highway; or how may people live within a 100
    year flood zone.

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-   A GIS can provide a basis for conducting complex spatial analyses
    such as the area, residents, and businesses that would be vulnerable
    from a chemical release from a fixed facility or an intersection.

##### *Resources Required for a GIS*

> **Question for the Class:** What is involved in building a GIS?
>
> *Developing a GIS involves investment in five areas: computer
> hardware, computer software, geographic data, procedures, and trained
> staff.*

-   *Computer Hardware: Desktop personal computers are increasing with
    dramatic speed to 266 MH with extensive RAM running Windows NT or
    Windows 95. The emergency manager should purchase the fastest
    computer on the market, with at least 64 Mb RAM with a large monitor
    (at least 17\"). A color printer that is capable of printing 17 by
    14 inches is essential; a plotter is useful for preparing large 36\"
    wide maps. A scanner is useful for including photographs or maps in
    a GIS.*

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-   *Computer Software: Several software companies are providing local
    and state governments excellent GIS programs. Intergraph's
    Geo-Media, ArcView, and MapInfo all have reasonably priced powerful
    software. Each of the shell software packages is fully capable of
    enabling emergency management agencies to complete complex hazard
    analysis.*

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-   *Geographic Data: Data will include relational databases that have
    either street address that can be geo-coded or geographic
    coordinates. The above software can either geo-code the databases or
    create points from the coordinate fields. Census Bureau TIGER
    street, highway, rail, and water features are available from
    distributors in common map projections. Feature image data (photos,
    satellite images, or USGS Quad sheets) are also available from
    either Federal or state agencies or commercial distributors in
    common projection formats.*

> ***Procedures:***
>
> *The "Manager's Guide" provides excellent recommendations for GIS
> procedures. The manner in which data is stored, analysis performed,
> maps prepared, or files shared must be established.*
>
> ***Training Staff and Technical Support:***
>
> *Training and technical support are critical to efficient operations
> and effective program operations.*
>
> *Staffing Requirements:*
>
> *The GIS technical staff person must understand file management,
> database formatting, and computer aided graphics drawing programs. If
> the staff member has these skills, the GIS program can be learned
> easily. In addition, skills in understanding computer networks will be
> helpful in ensuring that printers function, scanners work, and server
> files are available to the staff.*

*Instructor Note: Numerous graphics are included in this session of the
class. It is recommended that the instructor include the graphics in
PowerPoint or print the graphics using Microsoft Paint and make slides
for use in the class.*

**4.2. Geographic Spatial Object Concepts**

Geographic information systems include graphics that illustrate the
information about an area. The graphics may be either points, lines, or
polygons (enclosed areas). The following figure illustrates these
concepts.

***Point***

An object on the map represents a specific location for information. The
map object is defined by a single x, y coordinate pair. Each point
object is represented by a symbol style (e.g., circle, square, triangle,
etc.). The following map of Louisiana shows the location of cities in
the state. The cities would be points on the map.

> ![](media/image1.png){width="6.495833333333334in"
> height="5.0152777777777775in"}**Question for the Class:** What other
> points could be used in emergency management?
>
> *Location of special populations, resources, residents, hazard sites,
> churches, schools, and shelters.*

***Line***

A straight line feature joining two points. The line is a map object
defined by a set of sequential coordinates that may represent the
generalized shape of a geographic feature (e.g., street centerlines,
railroads, cables, stream or river). A street map is a collection of
thousands of line segments joining objects together. The following
illustration shows segments of the Louisiana State Highway system.

> **Question for the Class:** What other lines could be used in
> emergency management?
>
> *Location of water features by type including rivers, streams,
> drainage ditches, or canals.*

![](media/image2.png){width="6.495833333333334in"
height="5.0152777777777775in"}

***Polygon***

A polygon (area, parcel) is an area feature whose perimeter is defined
by a series of enclosing segments and nodes. A simple bounded region,
simple in the sense that it does not consist of more than one polygon
(where a boundary can consist of more than one polygon).

> **Question for the Class:** What other polygons could be used in
> emergency management? Examples of a polygon include the boundaries of
> a state, urban area, or county (parish) as illustrated below.
> Information about the urban area, county, or state may be attached to
> the data file that is associated with the graphic image.

##### *A Manager's Concern*

##### 

##### The "Manager's Overview" states that "GIS belongs to the class of computer systems that require the building of large databases before they become useful. Unlike many other micro-computer applications where a user can begin use after the purchase of the hardware and software, the use of a GIS requires that large spatial databases be created, appropriate hardware and software be purchased, applications be developed, and all components be installed, integrated and tested before users can begin to use the GIS" (p. 4). The authors suggest that because this is a complex and difficult task, extensive planning is required. Problems often occur because: 

-   The GIS is not integrated with other systems where interaction may
    be desired;

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-   Staff do not fully understand the technology prior to extensive
    training;

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-   Development time estimates differ from actual task time;

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-   GIS involves greater uncertainty about costs;

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-   A greater likelihood exists that programmatic changes (to other
    parts of the emergency management system) will be needed during the
    development phases.

"The significant management point here is that these are normal
conditions in the adoption of a new technology. Management needs to
anticipate that such events will happen, and when they do, take
appropriate management action" (p. 4). Since the introduction of a GIS
affects other elements of the emergency management process, it is an
opportunity to introduce fundamental change into the way emergency
management operates. Emergency managers must thus be involved in the
adoption of this new technology and help plan, implement, and monitor
the process.

##### 

> A key factor in the success of computer system adoption in the
> business world is the concept of the "enterprise" or "corporate"
> database. As implied by the name, the corporate database is a single,
> organization-wide data resource. The advantages of the corporate
> database are first, that all users have immediate and easy access to
> up-to-date information and, secondly that the construction of the
> database is done in the most efficient manner possible. (The Manager's
> Overview, p. 5)
>
> Establishing a corporate database is much more a question of policy,
> management cooperation and coordination, than some technical
> requirement.

The authors suggest that effective implementation of GIS is more than
technology. GIS requires data (databases, images, pictures, and
graphics) that are fundamental to the entire state or local agencies.
The emergency manager should realize that other agencies will be
interested in data layers, especially those that are maintained by the
emergency management unit (shelters, special populations, resources,
etc.). Emergency managers should thus seek out other local or state
units that are interested in jointly developing a GIS (planning, public
works, public safety, and education).

##### 

##### ![](media/image3.png){width="6.495833333333334in" height="5.0152777777777775in"}*Vector Data Layers*

***Vector:*** A coordinate-based data structure commonly used to
represent map features. Each object is represented as a list of
sequential x,y coordinates. Attributes may be associated with the
objects. The illustration below includes lines such as streets or roads,
the interstate, railroads, and water features. Hospitals are illustrated
by points on the map. The polygons include the boundaries of the City of
New Orleans, Orleans Parish, Lake Pontchartrain, and the Mississippi
River.

![](media/image4.png){width="6.495833333333334in"
height="5.0152777777777775in"}

***Longitude:*** Used to describe the East-West position of a point. The
position is reported as the number of degrees east (to - 180.0 degrees)
or west (to +180.0 degrees) of the prime meridian (0 degrees).
Represented by vertical lines running from the North to South poles.
Lines of longitude are farthest apart at the Equator and intersect at
both poles, and, therefore, are not parallel.

***Latitude:*** Used to describe the North-South position of a point as
measured usually in degrees or decimal degrees above or below the
equator. Latitude lines are the horizontal lines on a map that increase
from 0 degrees at the Equator to 90 degrees at both the North (+90.0
degrees) and South (-90.0 degrees) poles.

> **Question for the Class:** A key concern for the emergency manager is
> how accurate is the data. Should points mark the approximate location
> of a bridge, school building, and hospital?
>
> The manager should determine how accurate a specific piece of data is
> before using it in emergency management. Maps such as the
> USGS/Department of Commerce TIGER Files are approximate files and good
> for broad views of a local area. They are not suitable for engineering
> purposes. Review the section on TIGER Files that follows.

**4.3 Tiger Files**

***A Manager's Concern***

Tiger Files are some of the best data layers available for GIS
applications in emergency management. They were developed by the U.S.
Department of Commerce Census Bureau to assist in the census. Street and
water layers were taken from U.S.G.S. maps and edited to include street
and water feature names. The street files also include address ranges.
These files thus have been enhanced to allow for geo-coding of data
files that include street addresses. The Tiger files are the only
national source of street files that include address ranges. Although
many commercial vendors suggest that their maps are better than the
Tiger Files, in reality their maps were drawn from the Census Bureau
Tiger Files. Few commercial vendors have really enhanced these files. If
the Tiger Files have been enhanced, it has been done by local
communities that know the street names and have spent great effort to
correct street names, delete streets that are private roads, and add
street names to "unnamed street" files. The editing of the Tiger Files
must be done in collaboration with local officials.

The Bureau of the Census developed TIGER (Topologically Integrated
Geographic Encoding and Referencing System). It is based on the USGS
DLG-3 hydrographic and transportation data. Attribute data tied to the
topology include feature names, political and statistical geographic
area codes, county, incorporated place, census tract, and block
numbers), and potential address ranges and ZIP codes. These files are at
a scale of 1:100,000 as compared to more accurate mapping in the
U.S.G.S. 1:24,000 scale maps discussed below.

The U.S. Geological Survey Digital Line Graphs (DLG): The Survey
developed the topologically structured digital line graph format to
encode spatial and attribute data from the topographic quadrangle maps
usually at the USGS 7.5 minute and 1:24,000 scale. For more information
on the USGS files see: [http://www.usgs.gov](http://www.usgs.gov/).

##### 

##### *A Manager's Concern*

##### 

##### The development of GIS layers must address the following concerns.

-   What will be the source for each data layer (shelter locations,
    schools, hospitals, nursing homes, or emergency management
    resources)?

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-   Who will own the data layer?

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-   How will the new GIS layer be integrated with existing data files
    (lists of schools, hospitals, nursing homes, etc.)?

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-   Who will be responsible for updates to the data?

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-   How will the cost of the data be allocated?

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-   Will access to the data be made available to the public? How? By
    whom?

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-   Who will be responsible for archiving and retention of the data
    layer? . . of the original? . . of copies?

The "Manager's Guide" suggests that the data layers be prepared as a
team effort with other administrative agencies that are involved in the
emergency management system and who may use these up-to-date data
layers. Planning and input from a variety of public agencies is critical
in facilitating realistic expectations of the GIS.

##### ![](media/image5.png){width="6.495833333333334in" height="5.0152777777777775in"}4.4 Image Data

An image is a graphic representation or description of an object that is
typically produced by an optical or electronic device. Some common
examples of image data include remotely sensed data---such as satellite
data---scanned data and photographs. Image data such a photo is also
referred to as raster data. The raster image is displayed in a series of
grid-cells, or pixels; each has a certain value depending on how the
image was captured and what it represents. For example, if the image is
a remotely sensed satellite image, each pixel represents light energy
reflected from a portion of the Earth's surface. If, however, the image
is a scanned document, each pixel represents a brightness value
associated with a particular point on the document.

![](media/image6.png){width="6.495833333333334in"
height="5.0152777777777775in"}

With a GIS you can display image data and feature-based spatial data
together. The TIGER street network (feature-based data) can be placed
over an image (photograph). Combining these types of data is very useful
to the emergency manager.

> **Question for the Class:** What advantage does an image (photograph,
> satellite image) have over a feature based layer (street or water
> network, points of interest, or city/county boundary polygon)?
>
> *(For most people, a photo allows the viewer to gain a clearer
> perspective on the area viewed. We can see open farmland or forest in
> relation to water features of local road networks.)*

There are limitations to image data. The main limitation with image data
is that images do not contain data (attribute information) about what is
shown (the features they show).

A photo or satellite image is a *raster image.* It is a type of
computerized picture consisting of row after row of tiny dots (pixels).
Raster images are sometimes known as bitmaps. Aerial photographs,
scanned pictures, and satellite images are common types of raster data
found in GIS. A U.S.G.S. Quad Sheet is a common map used by emergency
managers. These maps appear to be similar to a state transportation road
map available from state transportation or tourist agencies. The Quad
Sheet Maps produced by the U.S. Geological Survey provide additional
data beyond roads and waterways, such as wetland areas. The details of
local areas are available on a national basis from the U.S. Geological
Survey as well as from many local surveying, mapping, or blueprint
vendors. The following illustration was scanned from a
![](media/image7.png){width="6.085416666666666in"
height="4.191666666666666in"}U.S.G.S. quad sheet.

Image data can be organized in a number of ways depending upon the
particular image format. Typically, the image data file contains a
header record that stores information about the image such as the number
of rows and columns in the image, the number of bits per pixel, the
color requirements and the geo-referencing information. Following the
image header is the actual pixel data for the image. The internal
organization of the image data is dependent upon the image format. Some
formats contain only a single band of data, while others contain
multiple bands.

**4.5 Geo-Coding**

Many organizations maintain large databases of events by address, such
as accident and crime reports, customer records, and tax and parcel
records. Addresses are, in fact, the most common form of storing
geographic data. With geo-coding, you can display the tabular
information in a computerized database containing addresses as points on
a map and find their locations on a map easily. Address geo-coding can
allow you to locate fire stations by entering their addresses, show
where all the students live in relation to the schools they attend, or
locate customers and thereby site facilities where the customers are
concentrated.

![](media/image8.png){width="6.495833333333334in"
height="5.0152777777777775in"}

An address specifies a location in the same way that a geographic
coordinate does. But since an address is merely a text string containing
the information of house number, street name, direction, and/or zip
codes, an address needs a mechanism for calculating the geographic
coordinate for the address and then displaying the location on a map
based on the assigned coordinate. To do so, addresses stored in tabular
data files must first be associated with a geographic feature, usually
in a street network. The coordinates of a data source can be used to
calculate and assign coordinates to addresses if the data source
features also have addresses. Geo-coding is the mechanism that allows
you to use addresses to identify locations on a map.

Geo-coding allows for the following functions:

-   You can create pin maps to show locations of various events by
    addresses. It is just the same as pushing stick pins onto a wall map
    to mark the locations of all branch offices of a bank.

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```
-   You can query and find geographic features using addresses.

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```
-   You can perform point-in-polygon analysis such as finding all
    customers within a trade zone.

There are a variety of planning, administrative and operational
activities which use geographic data in the form of addresses. A company
can match customer addresses against a street network of their
distributor service areas in order to know which distributor will handle
a customer. The information could also be used by emergency managers to
perform the following functions:

-   To analyze crimes by address. These locations can be mapped and
    analyzed with other demographic data.

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```
-   To enter an address, determine who should respond, and route
    emergency vehicles and personnel to the address.

```{=html}
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```
-   To match student addresses against a street map of a city. Once the
    homes of students are located, school assignments and busing plans
    can be created and analyzed.

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-   Identify potential impact of facilities storing hazardous materials
    in populated areas by matching the site addresses to a scheme
    containing census data.

###### 

**4.6 Global Positioning Systems**

This system of 24 Navstar satellites circle the earth every 12 hours at
an altitude of 12,000 miles above the earth, constantly transmitting the
precise time and their position in space. The system created a huge
commercial market for hand held GPS receivers and is used by emergency
response personnel including agencies such as police, fire, emergency
medical, public works. The unit measures a location to within 30 meters.
Drawing its power from flash light batteries and a small antenna, the
unit takes about 10 seconds to find and lock onto radio transmission
from at least three Navstar satellites.

GPS uses the triangulation of signals from the satellites to determine
locations on earth. GPS satellites know their location in space and
receivers can determine their distance from a satellite using the travel
time of a radio message from the satellite to the receiver.

Even with highly accurate atomic clocks, certain errors do creep into
the process of determining the ground position of the receiver. Selected
Availability (SA) is the program implemented by the U.S. Department of
Defense that makes GPS less accurate for non-military users for security
reasons. With SA in effect, the accuracy of the position on the ground
may be within 30 to 100 meters.

GPS products have been developed for many commercial applications. These
include surveying and mapping, aviation and marine navigation, vehicle
tracking systems and mobile computer and cellular platforms.

See: <http://www.gps4fun.com/gps_general.html>.

##### *Obtaining Maps* 

**Class Activity**

Using the Internet, provide the class with a demonstration of the
following sources of maps. Show how maps may be downloaded from these
Internet sites.

**1. U.S. Environmental Protection Agency:** EPA has a comprehensive GIS
Program. See its Internet site at <http://www.epa.gov/ngispr>.

**2. FEMA Map Service Center:** \[This description is taken from the
FEMA Internet site.\] FEMA's Map Service Center (MSC) provides online
access to National Flood Insurance Program (NFIP) Map Products. The MSC
Web site is designed to provide the latest information and support
services to users on flood related data.

In its continuing efforts to expand the availability of flood risk data,
FEMA's Mitigation Directorate has announced the release of the digital
Q3 Flood Data product for use in flood plain management, hazard
analysis, and risk assessment activities. The digital Q3 Flood Data
product is designed to serve the needs of FEMA's Response and Recovery
activities and flood insurance policy marketing initiatives.

FEMA intends to release digital Q3 Flood Data covering almost 900
counties across the United States by late 1996. These data will be
available in a variety of formats for use with desktop mapping and
geographic information systems. The digital Q3 Flood Data will be
provided through the Internet and on CD-ROM as part of MSC's
distribution and customer support services.

*Digital Q3 Flood Maps* are developed by scanning the existing FIRM hard
copy, vectoring a thematic overlay of flood risks. Vector Q3 Flood Data
files contain only certain features from the existing FIRM hard copy. Q3
vector data are contained in one single countywide file, including all
incorporated and unincorporated areas of a county.

Digital Q3 Flood Data do not replace the existing Flood Insurance Rate
Map (FIRM) hard copy or, if one exists, Digital Flood Insurance Rate Map
(DFIRM) product. The product is designed to support planning activities,
some Community Rating System activities, insurance marketing, and
mortgage portfolio reviews. It does not provide base flood elevation
information; thus, it has limited application for engineering analysis,
particularly for site design or rating flood insurance policies for
properties located within Special Flood Hazard Areas (SFHAs).

Digital Q3 Flood Data are not tied to a base map, are not used to
produce a new version of the FIRM hard copy, and are not subjected to
community review. The digital Q3 Flood Data are designed to provide
guidance and a general idea of the location of Special Flood Hazard
Areas.

The digital Q3 Flood Data product can be a valuable tool in screening
property addresses within a geographic information system to determine
flood risks. However, since the geographic processing performed to
develop digital Q3 flood data may introduce differences with the FIRM
hard copy source, users must apply considerable care and judgment in the
application of this product. For instance, digital Q3 flood data may be
overlaid on highly detailed large-scale community base mapping data;
but, if parcel level determinations are made, they must be prefaced with
information about the accuracy of the data from which they are derived.
To see more details on the Flood Insurance Rate Maps in digital form
see: <http://www.fema.gov/home/msc/q3flooda.htm>.

**3. U.S. Geological Survey:** GIS technology can be used for scientific
investigations, resource management, and development planning. For
access to FGDC *Manual of Geographic Data Products,* and USGS node of
the Federal Geo-spatial Data Clearinghouse, see:
<http://info.er.usgs.gov/research/gis/title.html>.

**4. Atlas.LSU.Edu**: A comprehensive, diverse set of maps for each
Louisiana Parish (County). Files include street/road, water, census
block group, parish boundaries, zip codes, city points, hospitals,
nursing homes, shelters, and schools in compressed ArcView shape files
suitable for using in ArcView 3.0 or earlier program. Images include
satellite photos for Louisiana and each Parish, as well as digital
raster images of each U.S.G.S. Quad sheet (1:24,000, 1:50:000 and 1:
1,000,000). Meta data for each layer is provided. To view the various
maps and files see: [http://atlas.lsu.edu](http://atlas.lsu.edu/).

**5. National Geophysical Data Center (NGDC)** Natural Hazards
Databases. A collection of databases and data on natural hazards. See
[http://www.ngdc.gov](http://www.ngdc.gov/).

> **Question for the Class:** In the past, what maps were used by
> emergency managers? How were they used? Given access to GIS, what
> types of maps could be created and how would they be used?

###### 4.7 FEMA Flood Insurance Rate Map (FIRM): A Case Study

**Class Assignment**

Review "FEMA Flood Insurance Rate Map Case Study" \[beginning on IG page
22\] and answer the following questions. Be prepared to discuss your
responses to the questions at the next class. (Copies of this case are
available in Readings: 4-Q3Case A Word document. In addition, the
reading "Digital Q3 Flood Data" is also available as an HTML document).

-   How should the digital flood maps be used in emergency management?

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-   What other layers of information would be useful in addition to the
    flood zone Q3 maps?

> ![](media/image9.png){width="6.495833333333334in"
> height="5.0152777777777775in"}**Question for the Class:** The FEMA A
> flood zones are displayed on the map above. How could the emergency
> manager use this type of display in emergency planning or response?
>
> A GIS allows users to select features in a layer (residents) that
> intersect with another layer (A Flood Zone). The attached list of
> residences \[at end of case study in IG\] was drawn from the above
> display using the GIS. These homes are in an A Flood Zone. How could
> the emergency manager use this list?

**Class Assignment: Using the FEMA FIRM Q3 Maps -- A Case Study**

Review the Case "Flood Insurance Rate Maps."

-   How should the digital FEMA Flood Maps be used in emergency
    management?

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-   What other layers of information would be useful to a local
    emergency manager in addition to the flood zone?

FEMA Flood Insurance Rate Maps Case Study

Adapted from the "User's Guide to the Q3 Digital Flood Maps," U.S. Flood
Insurance Administration, FEMA, Washington, DC, 1996.

**BACKGROUND**

**History of the National Flood Insurance Program**

In response to increasing losses from flood hazards nationwide, the
Congress of the United States passed the National Flood Insurance Act of
1968 which established the National Flood Insurance Program (NFIP). The
1968 Act provided for the availability of flood insurance within
communities that were willing to adopt floodplain management programs to
mitigate future flood losses. The act also required the identification
of all floodplain areas within the United States and the establishment
of flood-risk zones within those areas. As a result of the 1972
Hurricane Agnes flooding along the East coast, the 1968 Act was expanded
by the Flood Disaster Protection Act of 1973. The 1973 act added the
mandatory purchase requirement and increased the awareness of floodplain
mapping needs throughout the country. The responsibility for
administration of the NFIP belongs to the Federal Insurance
Administration of the Federal Emergency Management Agency (FEMA).

The risk data used to identify floodplain areas, as required by the Act,
are acquired through *flood insurance studies* (FISs). FISs are
hydrologic and hydraulic studies of flood risks, developed by FEMA.
Using the results of a FIS, FEMA prepares a flood insurance rate map
(FIRM) that depicts the spatial extent of *special flood hazard areas*
(SFHAs) and other thematic features related to flood risk assessment.
SFHAs are areas subject to inundation by a flood having a one-percent or
greater probability of being equaled or exceeded during any given year.
This flood, which is referred to as the 1% annual chance flood (or base
flood), is the national standard on which the floodplain management and
insurance requirements of the NFIP are based.

FEMA publishes the FIRM and distributes it to a wide range of users:
private citizens, community officials, insurance agents and brokers,
lending institutions, and other Federal agencies. The FIRM is the basis
for floodplain management, mitigation, and insurance activities of the
NFIP. Uses of the FIRM for insurance activities include enforcement of
the mandatory purchase requirement of the 1973 Act, which "requires the
purchase of flood insurance by property owners who are being assisted by
Federal programs or by Federally supervised, regulated, or insured
agencies or institutions in the acquisition or improvement of land or
facilities located or to be located in identified areas having special
flood hazards" (Section 2(b)(4) of the 1973 Act). In addition to the
identification of SFHAs, the risk zones shown on the FIRMs are the basis
for the establishment of premium rates for flood coverage offered
through the NFIP.

At present, FISs have been completed and FIRMs published for virtually
all communities in the nation having flood risks. Flood risks have been
assessed in approximately 20,400 communities nationwide. These studies,
conducted at a cost of over \$900 million, have resulted in the
publication of over 80,000 individual FIRM panels. Typically, 6 to 8
million FIRMs are distributed to users each year by FEMA. Over 2.5
million flood insurance policies have been written through the NFIP,
providing coverage against flood loss for over \$200 billion in property
nationwide. In addition to initial FISs, FEMA is responsible for
maintaining the FIRMs as communities grow, as new or better scientific
and technical data concerning flood risks becomes available, and as some
FISs become outdated by the construction of flood control projects or
the urbanization of rural watersheds. Several thousand FIRMs need to be
updated per year.

**Flood Data Product History**

Starting with Hurricane Hugo in 1989, FEMA has attempted to support
disaster relief operations with digital FIRMs. Disaster loan closings by
the Small Business Administration (SBA), Temporary Housing Programs, and
Individual Assistance and Family Grant Programs all require a flood
hazard assessment. With automated flood map reading to support these
assessments, significant time can be saved and map reading quality
improved, thus resulting in faster disaster relief for victims. More
recently, increased funding for post-disaster mitigation activities has
led to the extensive use of GIS and digital FIRMs for planning
activities. Applications include selection of sites for relocation,
prioritizing eligibility for home buyout programs, and identifying
repeatedly damaged properties in SFHAs.

To support disaster recovery operations, FEMA has developed
specifications for a digital flood map. The Q3 Flood Data product is
designed to serve FEMA's Response and Recovery activities as well as
flood insurance policy marketing initiatives. This product is designed
to allow rapid access to and distribution of digital FIRM data, and is
compatible with all existing digital FIRM data already available and
underway.

**Digital Flood Map (Q3)**

The Q3 Flood Data do not replace the existing hardcopy FIRM product. The
product has been designed to support planning activities, some Community
Rating System (CRS) activities, insurance marketing, and mortgage
portfolio review. It does not provide base flood elevation information;
thus, it has limited application for engineering analysis, particularly
for site design or rating of flood insurance policies for properties
located within SFHAs.

Q3 Flood Data are not tied to a base map, are not used to produce a new
version of the hardcopy FIRM, and are not subjected to community review.
Q3 Flood Data are intended to provide users with automated flood risk
data suitable for determining whether features are within or outside the
SFHA.

**USE POLICY**

**[Uses of Q3 Flood Data]{.underline}** The Q3 Flood Data are designed
to serve the needs of FEMA both for disaster response activities and for
other National Flood Insurance Program flood insurance activities. The
data are designed to answer basic in/out queries and questions about the
location of the special flood hazard area, but do not provide base flood
elevations. The Q3 Flood Data may be used in various GIS applications
with the caveat that sound judgement must be used in interpreting the Q3
Flood Data. For instance, the Q3 Flood Data may be overlaid on highly
detailed large scale community base mapping data; but, if parcel level
determinations are made, they must be prefaced with information about
the accuracy of the data from which they are derived.

The conversion of FIRMs to a digital format is expected to have many
benefits. However, users must bear in mind that the simple conversion of
FIRMs to a digital format does not inherently improve the engineering
quality of the product. Many of the difficulties with interpretation of
flood risk data, and the requirement for users to apply sound judgement
in methods selected for decision making and map interpretation remain
unchanged. **It should be noted that if a structure is determined to be
within or near the special flood hazard area by using a GIS, this
determination must be confirmed by continuing the printed hardcopy
FIRM.** Q3 Flood Data are not designed to be used for engineering
studies.

**Community Rating System**

For the purposes of the Community Rating System (CRS), Q3 Flood Data may
be used in the following ways:

-   for calculations of SFHA areas and similar applications that require
    geographic calculations and measures;

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-   for partial fulfillment of GIS provisions per the provisions of
    Section 440, "Flood Data Maintenance," as described in the *National
    Flood Insurance Program Community Rating System Coordinator's
    Manual* (Reference 5); and

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-   for development of "notification" lists of potentially flood-prone
    properties, per the provisions of Section 330; and

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-   for partial fulfillment of credits for the performance of flood
    determinations, when performed in conformance with guidelines for
    determination presented below.

**Flood Determinations**

The Q3 Flood Data can support flood determinations in a limited fashion,
in conformance with the "good faith" standard, if used within the
following guidelines:

-   The end user has obtained a source of address or property location
    data and combined it with Q3 Flood Data in a manner that conforms to
    the Standards of Care outlined above.

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-   The end user has made no determinations as to the flood prone status
    of a property that is within 250 feet of an SFHA boundary. This
    requirement is due to the accuracy, resolution, and variations of
    the Q3 Flood Data relative to the source FIRMs.

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-   The end user has verified that the Q3 Flood Data FIRM panel and
    suffix conform to the panel and suffix of the currently effective
    FIRM.

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-   The end user has confirmed the availability of flood insurance in
    the community for which the determination is to be offered.

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-   The end user has confirmed the zone and BFE with the source FIRM or
    DFIRM for properties located within 250 feet of the SFHA boundary or
    within the SFHA.

**The "Good Faith Standard"**

The mandatory flood insurance purchase requirements of the 1973 National
Flood Insurance Act apply only when a structure is located in an SFHA in
a community that is participating in the NFIP. Such a structure must be
insurable under the rules of the NFIP. Even though a portion of the land
parcel upon which the structure is planned or built may be within an
SFHA, the mandatory purchase requirement is triggered only if the
structure itself is within an SFHA.

The compliance of lenders with the mandatory flood insurance purchase
requirements of the 1973 Act is based on the "good faith standard."
Determining whether a structure is located in an area of special flood
hazard requires the examination of the location of the structure in
relationship to the areas of special flood hazard as shown on the
applicable FIRM. The good faith standard recognizes that despite FEMA's
best efforts to make the FIRMs as useful as possible, the descriptions
of SFHA areas, as depicted by some maps, may, in some instances, not be
clear enough to permit lenders to decide with certainty and precision
whether or not property that is the security for a loan or that is the
subject of financial assistance is located in such an area. It is for
this reason that FEMA has recommended a "good faith standard."

The good faith standard requires lenders to exercise "due diligence and
good faith" in determining the location of a property that is the
subject of a loan relative to areas of special flood hazards as shown on
a FIRM. This guidance is further explained, with additional information
on the 1973 Act, in the publication *Mandatory Purchase of Flood
Insurance Guidelines* (Reference 6). When determinations are being made
by lenders, or firms or individuals retained by lenders to assist in
these endeavors, collateral data in addition to the FIRM is frequently
required. FIRMs do not include all roads within communities, nor do they
depict address, property boundary, or structure location information. As
a result, determinations frequently can be made only by using an
ancillary source of data, such as a land parcel map, to determine the
location of a property on the FIRM.

Digital address range data, land parcel, and structure information is
available for many communities across the nation. Using these digital
data and GIS technology, it is possible to make determinations relative
to the 1973 Act and meet the good faith standard. However, the lenders
must assure that due diligence and good faith are exercised in
application of digital mapping systems to make determinations. Because
of both the increased complexity and the analytical capabilities of GIS,
assuring compliance with the good faith standard may require additional
effort relative to use of paper maps.

A prime concern is to assure that the accuracy of the digital base map
and structure location data are appropriate for use with the chosen
digital FIRM data set (DFIRM or Q3 Flood Data) to make determinations
relative to the 1973 Act. The concern for accuracy of the ancillary data
used with DFIRMs should increase in direct proportion to the relative
closeness of the property under analysis to the SFHA boundary. Thus,
lenders might not find it prudent to use digital data at the 1:100,000
scale as the primary source of information upon which to make a
determination regarding a property located within 250 feet of an SFHA.
Such caveats should be carefully considered when U.S. Bureau of the
Census TIGER data are used as the source from which property
determinations will be made.

> In some instances, GIS technology will enable the use of large-scale
> land parcel, topographic, structure, and other information, with
> digital FIRM data to make determinations. GIS technology allows maps
> to be created at any user-specified scale. Enlargement of scales does
> allow for precise determinations to be made. However, precise
> measurements are not inherently accurate. Accuracy can only be
> assessed from an appraisal of the quality of source data.

SFHA boundary information conveyed by Q3 Flood Data files was developed
to overlay USGS 7.5-minute topographic maps at a scale of 1:24,000.
Thus, Q3 Flood Data cannot be assumed to have an accuracy of better than
40 feet. Due to other limitations, FIA recommends that determinations
using GIS technology and Q3 Flood Data generally be made only when
structures are located 250 or more feet outside an SFHA boundary. In
cases where the structure is within 250 feet of the SFHA or inside the
SFHA, data such as the BFE determined from a FIS flood profile and the
surveyed lowest adjacent grade and/or lowest floor elevation should be
used to make a determination.

Prudence may require that a more conservative margin than 250 feet be
used to determine the need for ancillary data to support a GIS
determination. Terrain variations, the nature of flood hazards in the
area, and the quality of all digital data being used to make the
determination should be considered when establishing the need for
collecting survey and flood profile data.

\"Address\",\"City\",\"State\",\"Zip\"

172 Emory Ln, Deridder,LA,70634-7709

3589 Highway 389, Merryville,LA,70653-3710

152 Emory Ln, Deridder,LA,70634-7709

160 E Newman Rd, Ragley,LA,70657-3608

363 S A Cooley Rd, Longville,LA,70652-5209

316 Dewey Baggett Rd, Longville,LA,70652-5219

350 A B Bailey Rd, Deridder,LA,70634-8160

370 A B Bailey Rd, Deridder,LA,70634-8160

2148 Smyrna Rd, Deridder,LA,70634-7320

463 Patterson Rd, Longville,LA,70652-4029

630 Jeff Foshee Rd, Merryville,LA,70653-5405

480 Cedar St, Longville,LA,70652-3430

225 Old River Dam Rd, Merryville,LA,70653-3829

571 Jeff Foshee Rd, Merryville,LA,70653-5404

571 Jeff Foshee Rd, Merryville,LA,70653-5404

1528 Parish Line Rd, Deridder,LA,70634-4477

1531 Parish Line Rd, Deridder,LA,70634-4477

1189 Parish Line Rd, Deridder,LA,70634-4473

1471 Parish Line Rd, Deridder,LA,70634-4476

1803 Dr Beckom Dr, Deridder,LA,70634-5314

319 Fowler Rd, Deridder,LA,70634-4430

1166 Walter Singleton Rd,Dry Creek,LA,70637-3310

629 Jeff Foshee Rd, Merryville,LA,70653-5405

227 Henry Dougherty Rd, Longville,LA,70652-5216

529 Wingate Cemetery Rd,Merryville,LA,70653-3741

1121 S A Cooley Rd, Longville,LA,70652-5201

487 Bruce Quave Rd, Merryville,LA,70653-3717

113 Emory Ln, Deridder,LA,70634-7709

1058 Carpenter Rd, Deridder,LA,70634-7051

1084 Carpenter Rd, Deridder,LA,70634-7051

3139 Highway 389, Merryville,LA,70653-3706

410 Fowler Rd, Deridder,LA,70634-4431

181 Dickens Rd, Sugartown,LA,70662-3520

739 Fred Spikes Rd, Merryville,LA,70653-4043

3202 Highway 389, Merryville,LA,70653-3707

3240 Highway 389, Merryville,LA,70653-3707

204 April Rd, Merryville,LA,70653-5419

733 S A Cooley Rd, Longville,LA,70652-5205

669 Digger Franks Rd, Merryville,LA,70653-3820

653 S A Cooley Rd, Longville,LA,70652-5206

294 Vernon Cooley Rd, Longville,LA,70652-5223

716 Scallon Rd, Deridder,LA,70634-7434

105 Guernsey Dr, Ragley,LA,70657-3658

247 April Rd, Merryville,LA,70653-5419

289 April Rd, Merryville,LA,70653-5419

219 Jeff Foshee Rd, Merryville,LA,70653-5401

2477 Smyrna Rd, Deridder,LA,70634-7318

290 April Rd, Merryville,LA,70653-5419

107 Guernsey Dr, Ragley,LA,70657-3658