The Integration of Geospatial Technologies: GIS and GPS

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<ul><li>1.INTEGRATED GIS/GPS TECH 1Running Head: INTEGRATED GIS/GPS TECHThe Integration of Geospatial Technologies: Geographic Information System (GIS) and Global Positioning System (GPS) Lindsey LandolfiTowson University Geographic Information Systems Applications:Homeland Security and Emergency ManagementProfessor John Morgan August 2011 Landolfi</li></ul><p>2. INTEGRATED GIS/GPS TECH 2As 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 earths 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. 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 users 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. 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 toLandolfi 5. INTEGRATED GIS/GPS TECH 5successfully combine a features 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. 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 canLandolfi 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 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 anLandolfi 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. INTEG...</p>