The Integration of Geospatial Technologies: GIS and GPS

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The Integration of Geospatial Technologies: GIS and GPS

  1. 1. INTEGRATED GIS/GPS TECH 1Running 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 Landolfi
  2. 2. INTEGRATED GIS/GPS TECH 2 “As we move from an industrial economy to a knowledge-based economy, our relianceon physical infrastructure is being supplemented by reliance on knowledge infrastructure, ofwhich geographic knowledge will form a key component.” (Dangermond, 2010) The applicationof geographic information is pertinent to a wide range of users and purposes. Geospatialtechnologies such as the Geographic Information System (GIS) or the Global Positioning System(GPS) facilitate the implementation and exploitation of fundamental geographic data. Nationaland global federal agencies, state and local government, non-profit entities, private corporations,and academia implement enterprise applications and pervasive computing of geospatialtechnologies in order to develop strategy and support operations. It is important for governmentand public service organizations to develop and employ tools that most efficiently acquire andanalyze data. The use of integrated geospatial technologies can provide the best availableinformation to assist in decision making relevant to time and geography. This paper will providean overview of integrated geospatial technologies specifically the various methods of GIS andGPS integration, the benefits of integration, and provide real world examples of existingimplementations 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 integrateshardware, software, and data in order to cartographically present layers of geographicinformation such as environmental, area, or demographic data. Each layer of spatial data islinked to corresponding tabular information. Layers can be combined and manipulated asnecessary; linking all layers to a mutual coordinate system enables maps of different scales andprojections to properly overlay. With GIS large quantities of data are combined into a singleobject-relational database enabling users to easily search for individual features and associated Landolfi
  3. 3. INTEGRATED GIS/GPS TECH 3attributes or identify patterns by examining the distribution of features. Numerous federal, state,and local governments, private and nonprofit organizations use GIS to enhance geographicknowledge. GIS is a powerful tool for planning and decision-making in operations dependent onor related to geographic information. For example, The Federal Emergency Management Agency(FEMA) uses GIS capabilities in disaster preparation and response. The access anddissemination of available geographic information is supported by the FEMA Mapping andAnalysis Center (MAC); “in addition to managing a state-of-the-art GIS laboratory, the GIS staffengaged in GIS production and analysis for program offices throughout the Agency, including:the EST, the Readiness, Response and Recovery Directorate, the Federal Insurance andMitigation Administration, the Administration and Resource Planning Directorate, disaster fieldoffices, 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 radiosignals from the satellites to GPS receivers. A GPS receiver will attempt to sync with the satellitesignal based off of a basic pseudorandom bit pattern. The receiver will delay the start of its bitpattern to coordinate with the satellite; the length of the delay is used to calculate the distancebetween the receiver and satellite. AGPS receiver and a minimum of three satellites arenecessary to perform a triangulation and accurately determine the user‟s geographic position. SeeAPNDX figure 1 for an illustration of the interaction between GPS control, space, and usersegments. “The GPS constellation is designed and operated as a 24-satellite system, consisting ofsix 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. Landolfi
  4. 4. INTEGRATED GIS/GPS TECH 4This arrangement creates a robust and stable GPS constellation which guarantees constant accessto transmitting signals from at least four satellites to any location on the earth. “Real-world datacollected by the FAA show that some high-quality GPS SPS receivers currently provide betterthan 3 meter horizontal accuracy.” See APNDX figure 3 for GPS performance accuracyhistogram. The accuracy of data acquired by a GPS unit is influenced by the location and lengthan observation and the quality of a GPS receiver. All user-operated, satellite-based GPSreceivers comprise the user segment. The Air Force Space Command (AFSPC) monitors, andmaintains the GPS space and ground control segments. The GPS program is managed by TheNational 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 deputysecretaries of the Department of Defense and Transportation. “Its membership includesequivalent-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 theExecutive 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 anillustration of the NEC-PNT organizational structure. The Integration of GIS and GPS geospatial technologies couples GPS spatial positioningfunctionality with GIS ability to compute spatial relationships. GIS technology requires accuratefeature placement to best determine intricate spatial relationships. The GPS positional accuracyenhances the functioning of GIS by improving the spatial quality of GIS data. Typical sources ofGIS 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 Landolfi
  5. 5. INTEGRATED GIS/GPS TECH 5successfully combine a feature‟s accurate geographic coordinates and the correspondingattributes and values of that feature. Layers from a GIS dataset can be geo-referenced andprojected to the GPS data coordinate system providing a unified spatial representation. Thecombination of GIS layers and GPS coordinates ensure integrity and consistency in the digitalrepresentation of reality. Integration of these technologies is economically sensible since accuratefield collection of data is time consuming and is subject to human error. Erroneousmeasurements must be re-acquired in the field. Also it may require multiple individuals to obtaina single measurement opposed to a single hand-held system user. Converting existing referencemaps requires accuracy confirmation which would traditionally bring uses back to the field forconfirmation. Overall, combing GIS and GPS technologies will increase worker productivity andefficiency. There are various techniques to integrate GIS/GPS. Data integration may occur between aself contained GPS and PC operated GIS; data is collected and stored in the field with GPS andlater transferred to the GIS database. “An example of a data-focused solution is TrimbleNavigations GeoExplorer® 3, for data collection and update, with GPS Pathfinder® Office, fordata transfer and processing, and Esris ArcInfo or ArcView products, for spatial analysis, queryand archive.” (Harrington, 2000) See APNDX figure 5 for an illustration of data-focusedintegration. Data focused interaction is a commonly employed method of integration. A tighterlevel of integration is a position focused approach; the concept is a GPS system will supplygeodetic data to a GIS field device. The field device will extract and store the data into the GISdatabase. Handheld devices that feature software application for both GPS control and GIS fieldoperations are becoming increasingly common. “An example of position-focused integration isseen through the use of Trimble Navigations GPS Pathfinder Controller software to setup a GPS Landolfi
  6. 6. INTEGRATED GIS/GPS TECH 6Pathfinder XRS receiver for use with Esris ArcPad field-GIS product.” (Harrington, 2000) SeeAPNDX figure 6 for an illustration of position-focused integration using a single or two fielddevices. Once connected to the Pathfinder XRS receiver ArcPAD will provide interface and datastorage 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 technologyfocused integration. This method is truly integrated as the GPS technology can be completelyembedded 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 ofthe GPS hardware is executed directly by a GIS application allowing for total control of the GPSreceiver and two-way data flow. This method is advantageous since full GIS capabilities can betaken into the field. “An example of technology-focused integration is the use of TrimbleNavigations Pathfinder Tools software development kit to integrate a GPS Pathfinder XRSreceiver within a customized application that uses Esris MapObjects product to visually displaya 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 GISsoftware applications; “ESRI currently has an approximate 36 percent share of the GIS softwaremarket worldwide, more than any other vendor.” (ESRI, 2002) ESRI is an active member of theOpen Geospatial Consortium (OGC), an international voluntary consensus standardsorganization for geospatial technology, including GIS and GPS. The OGC Abstract Specificationdefines the framework for the OGC data interoperability standards and specifications forgeospatial technology development. OGS standards conceptually specify the interface, encoding,profile, application schema, and relationships across multiple platforms. GIS vendors can Landolfi
  7. 7. INTEGRATED GIS/GPS TECH 7validate compliance with OGS specifications by obtaining an official OGC compliancecertification. See APNDX figure 8 for a flow chart of the OGS Compliance Testing EvaluationProcedure. ArcGIS is a widely accepted OGC compliant certified GIS software suite producedby ESRI. “ArcGIS is a system that lets you easily author data, maps, globes, and models on thedesktop 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 leveragegeospatial information capabilities in server, mobile, or networked environments. ArcGIS includes a GPS tools bar which allows the user to track GPS devices connectedto a computer. Once connected to a GPS device it is possible to view the device data trackdirectly in the ArcMAP program. This data-focused method is economical as it does not requireadditional expensive software. The GPS data, essentially a list of coordinates, will be streamedinto an ArcGIS data-log. ArcGIS acquires and decodes the incoming GPS data according to theNMEA 0183 standard protocol defined by the National Marine Electronics Association. NMEA0183 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 seriesof 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 thereforeedits must be conducted in the field. This technique requires extensive editing to convert GPSdata into GIS features. ArcPAD is an out-of-the-box solution ESRI solution for GIS and GPS integration. Thistechnology focused form of integration eliminates interoperability challenges since data isdirectly exported and transformed to the ArcGIS system. When installed, ArcMAP will featurean ArcPAD and an ArcPAD data management tool bar. Tools convert outgoing data into an Landolfi
  8. 8. INTEGRATED GIS/GPS TECH 8ArcPAD compatible format so existing information from the GIS geo-database (GDB) can beaccessed on a GPS device and still look and behave as it does on ArcGIS. A handheld GPSdevice can be taken into the field using the same interface and functionality of ArcMAP. Thedevice maintains GPS capabilities, adding the functionality of GPS to GIS for the purpose ofdata collection and field navigation. When field data is collected with GPS device, the „check-indata‟ function in ArcPAD toolbar will transfer data back from the GPS device back to theArcGIS to be integrated with the existing GDB. “ArcPad uses data from a number of NMEA0183 sentences to display all of the information in the GPS Position Window as well as topopulate the fields associated with the GPS Tracklog.” (ESRI, n.d.) See APNDX figure 9 for alist of NMEA sentences and corresponding descriptions that are recognized by ArcPAD. Withthe use of ArcGIS extensions, data can be modified to allow for post-processing of data toachieve specified GPS accuracy. The ArcPAD field data application is designed for seamlessintegration with ArcMAP for GPS capable windows mobile devices therefore eliminating thetime consuming manual GPS to GIS data conversion process. Increased modality and decentralization of integrated geospatial systems extends from thearchitecture of servers and applications, to the availability of open source data on the web, tocrowd sourcing of geospatial data. Geospatial web service (GWS) technology is being developedand implemented for remote sensing data visualization, spatial analysis, and geo-rectification.GWS cross-platform capabilities support enhanced data integration ensuring the most effectiveuse of currently available geospatial technologies. Dynamic GWS capabilities are facilitated byimplementation compliance of the OGC and the World Wide Web Consortium (W3C) standards.“OGC Web Services provide a vendor-neutral, interoperable framework for web-baseddiscovery, access, integration, analysis, exploitation and visualization of multiple online geodata Landolfi
  9. 9. INTEGRATED GIS/GPS TECH 9sources, sensor-derived information, and geoprocessing capabilities.” (Tiwari, 2010) Thedevelopment of the GIS server to a standards based web platform will significantly increase theavailable access to geospatial information. Increased amounts of information is associated withincrease 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 mapprojection available to millions. The emergence of web oriented GIS systems has created possibilities for open sourceGIS and GPS applications. Interoperable GWS has the ability to support collaborative user datadistribution, creation, editing, and browsing. Open source GWS technology is promotingcollaborative development of geospatial data and services. The community based design of opensource GWS technologies is supplemented by volunteered geographic information (VGI).Crowd-sourced data is used to augment authoritative resources by contributing content todatabases. There is an array of geospatial applications which support a user enhanced datamodel. 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 suppliedcontent. 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 thatusers could set up their own map layer or feature class in the database and through Web editingtools, easily collect observation data using crowdsourcing.” Increased use of GWS data andservices will contribute to more evolved interfaced as GWS developers must constantlyaccommodate technology advances. The integration of crowd-sourcing methods with GWS is asignificant step in the democratization of GIS technology. Landolfi
  10. 10. INTEGRATED GIS/GPS TECH 10 There are concerns in respect to the usability of community crowd-sourced data. Thenature of volunteered geographic information has raised issues for example, safeguardingindividual privacy when using an integrated device to perform location-based service. It will benecessary to develop privacy solutions to guard personal information while sharing data in thegrowing GWS environment. Data pertinent concerns involve issues such as data ownership. “Atpresent, every OSM contributor agrees that their contributions can be used under the CreativeCommons Attribution/ShareAlike license, version 2 (CC-BY-SA 2.0, for short).” The currentlicensing for open-source data has three basic elements it is freely copiable, all derivatives of awork must be under a license compatible with the original (ShareAlike), and attribution to thecopyright owner is required. CC-BY-SA 2.0 is ambiguous in regards to the legal protection ofopen-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 datato be a national capital asset. Other concerns involve data use and implementation; there is ahigher probability of data misuse correlated with an increasing number of GIS users. It isnecessary for the abundance of available spatial data, specifically VGI data, to be properlymanaged. Data management can assist in maintaining a structured data collection formanipulation and analysis. The National Spatial Data Infrastructure (NSDI) and the FederalGeographic Data Committee (FGDC) coordinate the development, use, and dissemination ofgeospatial 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) NSDIcontributes to data integrity by confirming data accuracy, reducing data duplication, andeliminating erroneous data manipulation. Collaboration from a variety of government and publicFGDC partners, in respect to the NSDI, ensure that all user needs are being encompassed during Landolfi
  11. 11. INTEGRATED GIS/GPS TECH 11development. See APNDX figure 10 for an overview of the structure of the various componentsof the FGDC. NSDI is also responsible for the analysis of current situational trends in nationalinfrastructure and developing projections based on their data. By deciding what geospatial data isrelevant to a situation or audience and it is possible to provide the best applications suited tothose 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 spatialdata. GWS is responsible for homogeneously chaining multiple individual standard basedservices and data. The increased collaboration and communication across organizations isencouraging vendors to become more specialized. GWS reliability will be enhanced by theability for individual vendors to focus on data contribution related to their expertise. Users canthen source existing and reliable GWS data and services to develop custom solutions tailored to aclient‟s specific needs. GWS will assist in the reduction of data waste resulting from geospatialinformation that is discarded when it proves erroneous to or exceeds the purpose of a singleproject. Collected data that is nonessential for one project maybe considered useful in a differentapplication. Acquisition and conversion of raw data to a useful information format requiressignificant resources and knowledge. There is comparative timing and economic advantage ofopen-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 therapid access and availability to vast amounts of resources. GWS technology is beneficial whenprompt 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-processableformat (specifically WSDL). Other systems interact with the Web service in a manner prescribed Landolfi
  12. 12. INTEGRATED GIS/GPS TECH 12by its description using SOAP-messages.” (W3C, 2004) The GWS distributed system structuresupports interoperability with outside systems through variety of network architectures.Traditional mainframe or terminal processing model uses a central processing unit to support allterminal 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 distributegeospatial data over the Internet; the ArcIMS interface is driven by the web browser while theGIS and database the server side. See APNDX figure 11 for an illustration of ArcIMS softwareconfiguration. Terminal processing can also be applied for remote uses; mobile devices canfunction as a GIS terminal allowing for real-time reference and updates. Mobile devicesequipped with GPS functionality can connect to the central server to supply spatial positioningdata. See APNDX figure 12 for an outline of network GIS framework employing a mobiledevice terminal. This implies that GWS and GIS databases are capable of integrating real-timemeasurements such as traffic or weather. Peer to peer (P2P) networks are an inexpensive methodof directly connecting multiple systems though techniques such as a local area network (LAN) orwide area network (WAN). P2P use with GWS is limited by reduced software extensibility, lackof interoperability standards and security measures. Access to GWS data and services arerestricted to the capabilities of the client‟s system. The client-server model is a combination ofmainframe and P2P architecture; operational tasks are divided between the providing server andthe client. The client-server model is the most commonly implemented distributed applicationstructure for GWS. Web-based client/server systems help to minimize issues regarding datadistribution 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 Landolfi
  13. 13. INTEGRATED GIS/GPS TECH 13which have quickly incorporated into and enhanced modern daily life. These technologies havemade it possible to capture, manipulate, analyze, and visualize data from the field in real time.Integrated geospatial technologies offer interoperability, customization, and on-demand dataaccess. Additionally, these technologies are economically sensible. For example, it is no longernecessary to post process GPS geodetic data from the center location allowing for moreproductive field time. Also that GIS and GPS integration provide distance safety for fieldworkers while the increased spatial positioning accuracy can minimize risk of collateral damagewhen targeting a specific feature on a map. Military, commercial, and civil reliance on integrated geospatial technologies has madethese technologies fundamental to US critical, economical, and security infrastructures. The useof interoperable geospatial technologies in all societal sectors has become pervasive; thegeospatial industry is involved in the utilities segment, electric commerce, transportationindustry, law enforcement, the security market, financial services, military defense andoperations, education, urban planning, environmental management, and public safety such asemergency management. See APNDX figure 13 for an overview of integrated GIS applicationsin local government. The application of geospatial knowledge is limited only to humanimagination and implementation capabilities. The rapid advance of computer technology and theconvergence of GIS and GPS will continue to produce advanced geospatial products and servicesthat support an intelligent approach to societal and environmental design. Landolfi
  14. 14. INTEGRATED GIS/GPS TECH 14 ReferencesAir Force Space Command. (2010, September 15). Global Positioning System [Fact Sheet]. Retrieved from http://www.af.mil/information/factsheets/factsheet.asp?id=119Dangermond, J. (2010, Winter). Geographic Knowledge: Our New Infrastructure. ArcNews. Retrieved from http://www.esri.com/news/arcnews/winter1011articles/geographic- knowledge.htmlESRI. (2002, August). COTS GIS: The value of a commercial geographic information system. Retrieved from http://www.esri.com/library/whitepapers/pdfs/cots-gis.pdfESRI. (n.d.). NMEA 0183 sentences recognized by ArcPad. Retrieved from http://webhelp.esri.com/arcpad/8.0/userguide/index.htm# capture_devices/concept_nmea.htmESRI. (n.d.). Products. Retrieved from http://www.esri.com/products/index.htmlFEMA. (2004, September 22). Mapping and Analysis Center. Retrieved from http://www.gismaps.fema.gov/ gis02.shtmGeospatial 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.pdfHarrington, 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.htmLongley, 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=28982Peters (2003). System design strategies. ESRI White Paper, Environmental Systems Research Institute, Redlands, CA, http://www.esri.com/library/ Landolfi
  15. 15. INTEGRATED GIS/GPS TECH 15 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.pdfW3C, Haas, H., Brown, A., & Microsoft (Eds.). (2004, February 11). Web services glossary. Retrieved from http://www.w3.org/TR/ws-gloss/ Landolfi
  16. 16. INTEGRATED GIS/GPS TECH 16 AppendixFigure 1: GPS Control, Space, and User Segment InteractionImage Courtesy of the Aerospace CorporationFigure 2: GPS Satellite Constellation ArrangementImage Courtesy of the National Executive Committee for Space-Based PNT Landolfi
  17. 17. INTEGRATED GIS/GPS TECH 17Figure 3: GPS Performance AccuracyImage Courtesy of the National Executive Committee for Space-Based PNTFigure 4: NEC-PNT Organizational StructureImage Courtesy of the National Executive Committee for Space-Based PNT Landolfi
  18. 18. INTEGRATED GIS/GPS TECH 18Figure 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) Landolfi
  19. 19. INTEGRATED GIS/GPS TECH 19Figure 8: Flow chart of the OGS Compliance Testing Evaluation ProcedureImage Courtesy of the Open Geospatial ConsortiumFigure 9: ArcPad Recognized NMEA 0183 SentencesImage Courtesy of ESRI Landolfi
  20. 20. INTEGRATED GIS/GPS TECH 20Figure 11: ArcIMS (Internet Map Server) Software Configuration(Peters, 2003)Figure 10: the structure of the various components of the FGDCFederal Geographic Data Committee Landolfi
  21. 21. INTEGRATED GIS/GPS TECH 21Figure 12: Outline of Network GIS Framework(Takino, 2001)Figure 13: Integrated GIS Applications in Local Government Landolfi
  22. 22. INTEGRATED GIS/GPS TECH 22(Longley, 2005) Landolfi
  23. 23. INTEGRATED GIS/GPS TECH 23 Landolfi
  24. 24. INTEGRATED GIS/GPS TECH 24 Landolfi
  25. 25. INTEGRATED GIS/GPS TECH 25 Landolfi

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