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INTEGRATED GIS/GPS TECH 1

Running Head: INTEGRATED GIS/GPS TECH

The Integration of Geospatial Technologies:Geographic Information System (GIS) and Global Positioning System (GPS)

Lindsey Landolfi

Towson University

Geographic Information Systems Applications: Homeland Security and Emergency Management

Professor John Morgan

August 2011

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“As we move from an industrial economy to a knowledge-based economy, our reliance

on physical infrastructure is being supplemented by reliance on knowledge infrastructure, of

which geographic knowledge will form a key component.” (Dangermond, 2010) The application

of geographic information is pertinent to a wide range of users and purposes. Geospatial

technologies such as the Geographic Information System (GIS) or the Global Positioning System

(GPS) facilitate the implementation and exploitation of fundamental geographic data. National

and global federal agencies, state and local government, non-profit entities, private corporations,

and academia implement enterprise applications and pervasive computing of geospatial

technologies in order to develop strategy and support operations. It is important for government

and public service organizations to develop and employ tools that most efficiently acquire and

analyze data. The use of integrated geospatial technologies can provide the best available

information to assist in decision making relevant to time and geography. This paper will provide

an overview of integrated geospatial technologies specifically the various methods of GIS and

GPS integration, the benefits of integration, and provide real world examples of existing

implementations of integrated GIS and GPS applications.

Geographic Information System (GIS) technology is used to inventory, analyze, manage,

and display geodetic data as it is spatially referenced to the earth’s surface. GIS integrates

hardware, software, and data in order to cartographically present layers of geographic

information such as environmental, area, or demographic data. Each layer of spatial data is

linked to corresponding tabular information. Layers can be combined and manipulated as

necessary; linking all layers to a mutual coordinate system enables maps of different scales and

projections to properly overlay. With GIS large quantities of data are combined into a single

object-relational database enabling users to easily search for individual features and associated

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attributes or identify patterns by examining the distribution of features. Numerous federal, state,

and local governments, private and nonprofit organizations use GIS to enhance geographic

knowledge. GIS is a powerful tool for planning and decision-making in operations dependent on

or related to geographic information. For example, The Federal Emergency Management Agency

(FEMA) uses GIS capabilities in disaster preparation and response. The access and

dissemination of available geographic information is supported by the FEMA Mapping and

Analysis Center (MAC); “in addition to managing a state-of-the-art GIS laboratory, the GIS staff

engaged in GIS production and analysis for program offices throughout the Agency, including:

the EST, the Readiness, Response and Recovery Directorate, the Federal Insurance and

Mitigation Administration, the Administration and Resource Planning Directorate, disaster field

offices, the Office of National Preparedness and Homeland Security.” (FEMA, 2004)

Global Positioning System (GPS) is a free international utility developed by the U.S.

Department of Defense. GPS provides accurate space-based positioning, navigation, and timing

(PNT) capabilities and services to GPS receivers.GPS data is continually transmitted via radio

signals from the satellites to GPS receivers. A GPS receiver will attempt to sync with the satellite

signal based off of a basic pseudorandom bit pattern. The receiver will delay the start of its bit

pattern to coordinate with the satellite; the length of the delay is used to calculate the distance

between the receiver and satellite. AGPS receiver and a minimum of three satellites are

necessary to perform a triangulation and accurately determine the user’s geographic position. See

APNDX figure 1 for an illustration of the interaction between GPS control, space, and user

segments. “The GPS constellation is designed and operated as a 24-satellite system, consisting of

six orbital planes, with a minimum of four satellites per plane.” (Air Force Space Command,

2010) See APNDX figure 2 for an illustration of the GPS satellite constellation arrangement.

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This arrangement creates a robust and stable GPS constellation which guarantees constant access

to transmitting signals from at least four satellites to any location on the earth. “Real-world data

collected by the FAA show that some high-quality GPS SPS receivers currently provide better

than 3 meter horizontal accuracy.” See APNDX figure 3 for GPS performance accuracy

histogram. The accuracy of data acquired by a GPS unit is influenced by the location and length

an observation and the quality of a GPS receiver. All user-operated, satellite-based GPS

receivers comprise the user segment. The Air Force Space Command (AFSPC) monitors, and

maintains the GPS space and ground control segments. The GPS program is managed by The

National Executive Committee for Space-Based Positioning, Navigation, and Timing (NEC-

PNT), a military and civil interagency. NEC-PNT is responsible for developing, advising,

coordinating, and overseeing the national PNT Strategy. NEC-PNT is co-chaired by the deputy

secretaries of the Department of Defense and Transportation. “Its membership includes

equivalent-level officials from the Departments of State, the Interior, Agriculture, Commerce,

and Homeland Security, as well as the Joint Chiefs of Staff and NASA. Components of the

Executive Office of the President participate as observers to the National Executive Committee,

and the FCC Chairman participates as a liaison.” (NEC-PNT, 2009) See APNDX figure 4 for an

illustration of the NEC-PNT organizational structure.

The Integration of GIS and GPS geospatial technologies couples GPS spatial positioning

functionality with GIS ability to compute spatial relationships. GIS technology requires accurate

feature placement to best determine intricate spatial relationships. The GPS positional accuracy

enhances the functioning of GIS by improving the spatial quality of GIS data. Typical sources of

GIS geographic information are field survey data, digitize graphical data, aerial photography,

and satellite imagery. The integration of GPS as a spatial data source for GIS makes it possible to

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successfully combine a feature’s accurate geographic coordinates and the corresponding

attributes and values of that feature. Layers from a GIS dataset can be geo-referenced and

projected to the GPS data coordinate system providing a unified spatial representation. The

combination of GIS layers and GPS coordinates ensure integrity and consistency in the digital

representation of reality. Integration of these technologies is economically sensible since accurate

field collection of data is time consuming and is subject to human error. Erroneous

measurements must be re-acquired in the field. Also it may require multiple individuals to obtain

a single measurement opposed to a single hand-held system user. Converting existing reference

maps requires accuracy confirmation which would traditionally bring uses back to the field for

confirmation. Overall, combing GIS and GPS technologies will increase worker productivity and

efficiency.

There are various techniques to integrate GIS/GPS. Data integration may occur between a

self contained GPS and PC operated GIS; data is collected and stored in the field with GPS and

later transferred to the GIS database. “An example of a data-focused solution is Trimble

Navigation's GeoExplorer® 3, for data collection and update, with GPS Pathfinder® Office, for

data transfer and processing, and Esri's ArcInfo or ArcView products, for spatial analysis, query

and archive.” (Harrington, 2000) See APNDX figure 5 for an illustration of data-focused

integration. Data focused interaction is a commonly employed method of integration. A tighter

level of integration is a position focused approach; the concept is a GPS system will supply

geodetic data to a GIS field device. The field device will extract and store the data into the GIS

database. Handheld devices that feature software application for both GPS control and GIS field

operations are becoming increasingly common. “An example of position-focused integration is

seen through the use of Trimble Navigation's GPS Pathfinder Controller software to setup a GPS

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Pathfinder XRS receiver for use with Esri's ArcPad field-GIS product.” (Harrington, 2000) See

APNDX figure 6 for an illustration of position-focused integration using a single or two field

devices. Once connected to the Pathfinder XRS receiver ArcPAD will provide interface and data

storage while the GPS Pathfinder XRS still acts as the controlling device for the GPS receiver.

The rapidly progressive field of software technology has paved the way for technology

focused integration. This method is truly integrated as the GPS technology can be completely

embedded within a GIS application. Fully integrated GIS/GPS technology is based off of a geo-

relational model which links spatial data files to data stored in the relational database. Control of

the GPS hardware is executed directly by a GIS application allowing for total control of the GPS

receiver and two-way data flow. This method is advantageous since full GIS capabilities can be

taken into the field. “An example of technology-focused integration is the use of Trimble

Navigation's Pathfinder Tools software development kit to integrate a GPS Pathfinder XRS

receiver within a customized application that uses Esri's MapObjects product to visually display

a map and carry out spatial analysis directly on a pen-based field computer.” (Harrington, 2000)

See APNDX figure 7 for an illustration of technology-focused integration.

The Economic and Social Research Institute (ESRI) is the industry leader for GIS

software applications; “ESRI currently has an approximate 36 percent share of the GIS software

market worldwide, more than any other vendor.” (ESRI, 2002) ESRI is an active member of the

Open Geospatial Consortium (OGC), an international voluntary consensus standards

organization for geospatial technology, including GIS and GPS. The OGC Abstract Specification

defines the framework for the OGC data interoperability standards and specifications for

geospatial technology development. OGS standards conceptually specify the interface, encoding,

profile, application schema, and relationships across multiple platforms. GIS vendors can

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validate compliance with OGS specifications by obtaining an official OGC compliance

certification. See APNDX figure 8 for a flow chart of the OGS Compliance Testing Evaluation

Procedure. ArcGIS is a widely accepted OGC compliant certified GIS software suite produced

by ESRI. “ArcGIS is a system that lets you easily author data, maps, globes, and models on the

desktop and serve them out for use on a desktop, in a browser, or in the field via mobile devices,

depending on the needs of your organization.” (ESRI, n.d.) ArcGIS suite software can leverage

geospatial information capabilities in server, mobile, or networked environments.

ArcGIS includes a GPS tools bar which allows the user to track GPS devices connected

to a computer. Once connected to a GPS device it is possible to view the device data track

directly in the ArcMAP program. This data-focused method is economical as it does not require

additional expensive software. The GPS data, essentially a list of coordinates, will be streamed

into an ArcGIS data-log. ArcGIS acquires and decodes the incoming GPS data according to the

NMEA 0183 standard protocol defined by the National Marine Electronics Association. NMEA

0183 protocol specifies how GPS devices communicate with other external devices such as GIS;

the NMEA 0183 protocol definition is available from http://www.nmea.org. NMEA uses a series

of standard sentence formats in ASCII (American Standard Code for Information Interchange)

text to convey data. Data streamed through the GPS tool bar can not be post-processed therefore

edits must be conducted in the field. This technique requires extensive editing to convert GPS

data into GIS features.

ArcPAD is an out-of-the-box solution ESRI solution for GIS and GPS integration. This

technology focused form of integration eliminates interoperability challenges since data is

directly exported and transformed to the ArcGIS system. When installed, ArcMAP will feature

an ArcPAD and an ArcPAD data management tool bar. Tools convert outgoing data into an

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ArcPAD compatible format so existing information from the GIS geo-database (GDB) can be

accessed on a GPS device and still look and behave as it does on ArcGIS. A handheld GPS

device can be taken into the field using the same interface and functionality of ArcMAP. The

device maintains GPS capabilities, adding the functionality of GPS to GIS for the purpose of

data collection and field navigation. When field data is collected with GPS device, the ‘check-in

data’ function in ArcPAD toolbar will transfer data back from the GPS device back to the

ArcGIS to be integrated with the existing GDB. “ArcPad uses data from a number of NMEA

0183 sentences to display all of the information in the GPS Position Window as well as to

populate the fields associated with the GPS Tracklog.” (ESRI, n.d.) See APNDX figure 9 for a

list of NMEA sentences and corresponding descriptions that are recognized by ArcPAD. With

the use of ArcGIS extensions, data can be modified to allow for post-processing of data to

achieve specified GPS accuracy. The ArcPAD field data application is designed for seamless

integration with ArcMAP for GPS capable windows mobile devices therefore eliminating the

time consuming manual GPS to GIS data conversion process.

Increased modality and decentralization of integrated geospatial systems extends from the

architecture of servers and applications, to the availability of open source data on the web, to

crowd sourcing of geospatial data. Geospatial web service (GWS) technology is being developed

and implemented for remote sensing data visualization, spatial analysis, and geo-rectification.

GWS cross-platform capabilities support enhanced data integration ensuring the most effective

use of currently available geospatial technologies. Dynamic GWS capabilities are facilitated by

implementation compliance of the OGC and the World Wide Web Consortium (W3C) standards.

“OGC Web Services provide a vendor-neutral, interoperable framework for web-based

discovery, access, integration, analysis, exploitation and visualization of multiple online geodata

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sources, sensor-derived information, and geoprocessing capabilities.” (Tiwari, 2010) The

development of the GIS server to a standards based web platform will significantly increase the

available access to geospatial information. Increased amounts of information is associated with

increase opportunity for civil or government research. GWS hosted data content, data exchange,

and documentation could result in a rich, GPS enhanced, GIS produced multi-layered map

projection available to millions.

The emergence of web oriented GIS systems has created possibilities for open source

GIS and GPS applications. Interoperable GWS has the ability to support collaborative user data

distribution, creation, editing, and browsing. Open source GWS technology is promoting

collaborative development of geospatial data and services. The community based design of open

source GWS technologies is supplemented by volunteered geographic information (VGI).

Crowd-sourced data is used to augment authoritative resources by contributing content to

databases. There is an array of geospatial applications which support a user enhanced data

model. Among the first majorly successful crowd-sourced maps was the Open Street Map

(OSM). The OSM is a publicly available GPS enhanced street map enriched by user supplied

content. According to the ESRI President (J. Dangermond, Personal Interview, January 2011)

“Esri adopted this concept of building an ontology on a server and built it into ArcGIS 10 so that

users could set up their own map layer or feature class in the database and through Web editing

tools, easily collect observation data using crowdsourcing.” Increased use of GWS data and

services will contribute to more evolved interfaced as GWS developers must constantly

accommodate technology advances. The integration of crowd-sourcing methods with GWS is a

significant step in the democratization of GIS technology.

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There are concerns in respect to the usability of community crowd-sourced data. The

nature of volunteered geographic information has raised issues for example, safeguarding

individual privacy when using an integrated device to perform location-based service. It will be

necessary to develop privacy solutions to guard personal information while sharing data in the

growing GWS environment. Data pertinent concerns involve issues such as data ownership. “At

present, every OSM contributor agrees that their contributions can be used under the Creative

Commons Attribution/ShareAlike license, version 2 (CC-BY-SA 2.0, for short).” The current

licensing for open-source data has three basic elements it is freely copiable, all derivatives of a

work must be under a license compatible with the original (ShareAlike), and attribution to the

copyright owner is required. CC-BY-SA 2.0 is ambiguous in regards to the legal protection of

open-sourced geographical data, for example who to attribute or ShareAlike. Additionally, CC-

BY-SA 2.0 is not internationally embraced a major issue for a country who considers spatial data

to be a national capital asset. Other concerns involve data use and implementation; there is a

higher probability of data misuse correlated with an increasing number of GIS users. It is

necessary for the abundance of available spatial data, specifically VGI data, to be properly

managed. Data management can assist in maintaining a structured data collection for

manipulation and analysis. The National Spatial Data Infrastructure (NSDI) and the Federal

Geographic Data Committee (FGDC) coordinate the development, use, and dissemination of

geospatial data. “NSDI ensures that spatial information is accurate and available to state, local,

and tribal governments as well as to academia and the private sector.” (Tiwari, 2010) NSDI

contributes to data integrity by confirming data accuracy, reducing data duplication, and

eliminating erroneous data manipulation. Collaboration from a variety of government and public

FGDC partners, in respect to the NSDI, ensure that all user needs are being encompassed during

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development. See APNDX figure 10 for an overview of the structure of the various components

of the FGDC. NSDI is also responsible for the analysis of current situational trends in national

infrastructure and developing projections based on their data. By deciding what geospatial data is

relevant to a situation or audience and it is possible to provide the best applications suited to

those needs for example which features to include and the accuracy of feature location.

Overall, GWS is an effective solution for accessing and processing large scale spatial

data. GWS is responsible for homogeneously chaining multiple individual standard based

services and data. The increased collaboration and communication across organizations is

encouraging vendors to become more specialized. GWS reliability will be enhanced by the

ability for individual vendors to focus on data contribution related to their expertise. Users can

then source existing and reliable GWS data and services to develop custom solutions tailored to a

client’s specific needs. GWS will assist in the reduction of data waste resulting from geospatial

information that is discarded when it proves erroneous to or exceeds the purpose of a single

project. Collected data that is nonessential for one project maybe considered useful in a different

application. Acquisition and conversion of raw data to a useful information format requires

significant resources and knowledge. There is comparative timing and economic advantage of

open-sourced GWS and crowd-sourcing over the complex processing of raw geospatial data.

GWS provided geo-databases are advantageous over conventional databases in respect to the

rapid access and availability to vast amounts of resources. GWS technology is beneficial when

prompt access to geospatial information is necessary such as an emergency operation.

“A Web service is a software system designed to support interoperable machine-to-

machine interaction over a network. It has an interface described in a machine-processable

format (specifically WSDL). Other systems interact with the Web service in a manner prescribed

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by its description using SOAP-messages.” (W3C, 2004) The GWS distributed system structure

supports interoperability with outside systems through variety of network architectures.

Traditional mainframe or terminal processing model uses a central processing unit to support all

terminal activities. GWS applications can be provided to uses through terminal service sessions.

For example, ESRI’s Internet Mapping Software (IMS) ArcIMS uses this approach to distribute

geospatial data over the Internet; the ArcIMS interface is driven by the web browser while the

GIS and database the server side. See APNDX figure 11 for an illustration of ArcIMS software

configuration. Terminal processing can also be applied for remote uses; mobile devices can

function as a GIS terminal allowing for real-time reference and updates. Mobile devices

equipped with GPS functionality can connect to the central server to supply spatial positioning

data. See APNDX figure 12 for an outline of network GIS framework employing a mobile

device terminal. This implies that GWS and GIS databases are capable of integrating real-time

measurements such as traffic or weather. Peer to peer (P2P) networks are an inexpensive method

of directly connecting multiple systems though techniques such as a local area network (LAN) or

wide area network (WAN). P2P use with GWS is limited by reduced software extensibility, lack

of interoperability standards and security measures. Access to GWS data and services are

restricted to the capabilities of the client’s system. The client-server model is a combination of

mainframe and P2P architecture; operational tasks are divided between the providing server and

the client. The client-server model is the most commonly implemented distributed application

structure for GWS. Web-based client/server systems help to minimize issues regarding data

distribution flexibility and control.

Geospatial technology has an increasing impact and significance on society.

Integrated GIS and GPS technology has led to the development of many productive applications

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which have quickly incorporated into and enhanced modern daily life. These technologies have

made it possible to capture, manipulate, analyze, and visualize data from the field in real time.

Integrated geospatial technologies offer interoperability, customization, and on-demand data

access. Additionally, these technologies are economically sensible. For example, it is no longer

necessary to post process GPS geodetic data from the center location allowing for more

productive field time. Also that GIS and GPS integration provide distance safety for field

workers while the increased spatial positioning accuracy can minimize risk of collateral damage

when targeting a specific feature on a map.

Military, commercial, and civil reliance on integrated geospatial technologies has made

these technologies fundamental to US critical, economical, and security infrastructures. The use

of interoperable geospatial technologies in all societal sectors has become pervasive; the

geospatial industry is involved in the utilities segment, electric commerce, transportation

industry, law enforcement, the security market, financial services, military defense and

operations, education, urban planning, environmental management, and public safety such as

emergency management. See APNDX figure 13 for an overview of integrated GIS applications

in local government. The application of geospatial knowledge is limited only to human

imagination and implementation capabilities. The rapid advance of computer technology and the

convergence of GIS and GPS will continue to produce advanced geospatial products and services

that support an intelligent approach to societal and environmental design.

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References

Air Force Space Command. (2010, September 15). Global Positioning System [Fact Sheet]. Retrieved from http://www.af.mil/information/factsheets/factsheet.asp?id=119

Dangermond, J. (2010, Winter). Geographic Knowledge: Our New Infrastructure. ArcNews. Retrieved from http://www.esri.com/news/arcnews/winter1011articles/geographic-knowledge.html

ESRI. (2002, August). COTS GIS: The value of a commercial geographic information system. Retrieved from http://www.esri.com/library/whitepapers/pdfs/cots-gis.pdf

ESRI. (n.d.). NMEA 0183 sentences recognized by ArcPad. Retrieved from http://webhelp.esri.com/arcpad/8.0/userguide/index.htm#capture_devices/concept_nmea.htm

ESRI. (n.d.). Products. Retrieved from http://www.esri.com/products/index.html

FEMA. (2004, September 22). Mapping and Analysis Center. Retrieved from http://www.gismaps.fema.gov/ gis02.shtm

Geospatial Worlds (Interviewer) & Dangermond, J. (Interviewee). (2011, January). A ‘new geospatial modality’ [Interview transcript]. Retrieved from Geospatial World Web site: http://www.geospatialworld.net/media/Interview_Jack-Dangermond.pdf

Harrington, A. (2000). GIS and GPS: Technologies that work well together. Esri International User Conference Retrieved from http://proceedings.esri.com/library/userconf/proc00/professional/papers/PAP169/p169.htm

Longley, P., Goodchild, M., Maguire, D., & Rhind, D. (2005). Geographic information systems and science (2nd ed.). Hoboken, NJ: John Wiley & Sons Ltd.

National Executive Committee for Space-Based PNT. (2011, June 6). GPS Accuracy. Retrieved from http://www.gps.gov/systems/gps/performance/accuracy/

National Executive Committee for Space-Based PNT. (2009, March 04). National Executive Committee Membership. In Space-Based Positioning, Navigation, and Timing National Executive Committee. Retrieved from http://www.pnt.gov/

Open Geospatial Consortium. (2011). The Compliance Testing Program Policies & Procedures (L. Bermudez & S. Bacharach, Eds.) (Rep. No. 08-134r4). Retrieved from portal.opengeospatial.org/files/?artifact_id=28982

Peters (2003). System design strategies. ESRI White Paper, EnvironmentalSystems Research Institute, Redlands, CA, http://www.esri.com/library/

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whitepapers/pdfs/sysdesig.pdf.

Takino S. (2001), “GIS on the fly » to realize wireless GIS nnetwork by Java mobile phone,” Proceedings of the Second, International Conference on Web Information Systems Engineering, C. Claramunt, W. Winiwarter, Y. Kambayashi, Y. Zhang (Eds.),Volume: 2 , 76-84.

Tiwari, R. (2010, September 30). Architectures. Retrieved from University of Minnesota website: http://www-users.cs.umn.edu/~tiwrupa/HW1_T1.pdf

W3C, Haas, H., Brown, A., & Microsoft (Eds.). (2004, February 11). Web services glossary. Retrieved from http://www.w3.org/TR/ws-gloss/

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Appendix

Figure 1: GPS Control, Space, and User Segment Interaction

Image Courtesy of the Aerospace Corporation

Figure 2: GPS Satellite Constellation Arrangement

Image Courtesy of the National Executive Committee for Space-Based PNT

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Figure 3: GPS Performance Accuracy


Figure 4: NEC-PNT Organizational Structure


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Figure 5: Data-Focused Integration

(Harrington, 2000)

Figure 6: Position-Focused Integration Using a Single or Two Field Devices

(Harrington, 2000)

Figure 7: Technology-Focused Integration

(Harrington, 2000)

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Figure 8: Flow chart of the OGS Compliance Testing Evaluation Procedure

Image Courtesy of the Open Geospatial Consortium

Figure 9: ArcPad Recognized NMEA 0183 Sentences

Image Courtesy of ESRI

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Figure 11: ArcIMS (Internet Map Server) Software Configuration

(Peters, 2003)

Figure 10: the structure of the various components of the FGDC

Federal Geographic Data Committee

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Figure 12: Outline of Network GIS Framework

(Takino, 2001)

Figure 13: Integrated GIS Applications in Local Government

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(Longley, 2005)

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