276 Location-Based Services Time of Arrival (TOA): The position of a device can be determined by measuring the transferring-time of a signal between the device and the COO. Time Difference of Arrival (TDOA): Deter- mining a more precise position information of a device by taking advantage of a cells infrastructure and measuring the transferring time of a device to three or more antennas. Ubiquitous Information Management (UIM): A communication concept, which is free from temporal and, in general, from spatial constraints. Ultra Wideband (UWB): A technology which enables very short-range positioning in- formation. 277 Chapter XXXV Coupling GPS and GIS Mahbubur R. Meenar Temple University, USA John A. Sorrentino Temple University, USA Sharmin Yesmin Temple University, USA Copyright © 2009, IGI Global, distributing in print or electronic forms without written permission of IGI Global is prohibited. Abstr Act Since the 1990s, the integration of GPS and GIS has become more and more popular and an industry standard in the GIS community worldwide. The increasing availability and affordability of mobile GIS and GPS, along with greater data accuracy and interoperability, will only ensure steady growth of this practice in the future. This chapter provides a brief background of GPS technology and its use in GIS, and then elaborates on the integration techniques of both technologies within their limitations. It also highlights data processing, transfer, and maintenance issues and future trends of this integration. Introduct Ion The use of the Global Positioning System (GPS) as a method of collecting locational data for Geo- graphic Information Systems (GIS) is increasing in popularity in the GIS community. GIS data is dynamic – it changes over time, and GPS is an effective way to track those changes (Steede-Terry, 2000). According to Environmental Systems Research Institute (ESRI) president Jack Dan- germond, GPS is “uniquely suited to integration with GIS. Whether the object of concern is moving or not, whether concern is for a certain place at a certain time, a series of places over time, or a place with no regard to time, GPS can measure it, locate it, track it.” (Steede-Terry, 2000). 278 Coupling GPS and GIS Although GIS was available in the market in the 1970s, and GPS in the 1980s, it was only in the mid- 1990s that people started using GPS coupled to GIS. The GPS technology and its analogs (Global Navigation Satellite System or GLONASS in Rus- sia and the proposed Galileo system in Europe) have proven to be the most cost-effective, fastest, and most accurate methods of providing location information (Longley et. al, 2005; Trimble, 2002; Taylor et. al, 2001). Organizations that maintain GIS databases – be they local governments or oil companies – can easily and accurately inventory either stationary or moving things and add those locations to their databases (Imran et. al, 2006; Steede-Terry, 2000). Some common applications of coupling GPS and GIS are surveying, crime mapping, animal tracking, trafc management, emergency management, road construction, and vehicle navigation. bAckground need for gps data in gIs When people try to nd out where on earth they are located, they rely on either absolute coordi- nates with latitude and longitude information or relative coordinates where location information is expressed with the help of another location (Ken- nedy, 2002). GIS maps can be created or corrected from the features entered in the eld using a GPS receiver (Maantay and Ziegler, 2006). Thus people can know their actual positions on earth and then compare their locations in relation to other objects represented in a GIS map (Thurston et. al, 2003; Kennedy, 2002). GIS uses mainly two types of datasets: (a) primary, which is created by the user; and (b) secondary, which is collected or purchased from somewhere else. In GIS, primary data can be created by drawing any feature based on given dimensions, by digitizing ortho-photos, and by analyzing survey, remote sensing, and GPS data. Using GPS, primary data can be collected ac- curately and quickly with a common reference system without any drawing or digitizing opera- tion. Once the primary data is created, it can be distributed to others and be used as secondary data. Before using GPS as a primary data collec- tion tool for GIS, the users need to understand the GPS technology and its limitations. The GPS Technology The GPS data can be collected from a constellation of active satellites which continuously transmit coded signals to receivers and receive correctional data from monitoring stations. GPS receivers process the signals to compute latitude, longitude, and altitude of an object on earth (Giaglis, 2005; Kennedy, 2002). A method, known as triangulation, is used to calculate the position of any feature with the known distances from three xed locations (Le- tham, 2001). However, a discrepancy between satellite and receiver timing of just 1/100th of a second could make for a misreading of 1,860 miles (Steede-Terry, 2000). Therefore, a signal from a fourth satellite is needed to synchronize the time between the satellites and the receivers (Maantay and Ziegler, 2006; Longley et. al, 2005; Letham, 2001). To address this fact, the satellites have been deployed in a pattern that has each one passing over a monitoring station every twelve hours, with at least four visible in the sky all the times (Steede-Terry, 2000). The United States Navigation Satellite Timing and Ranging GPS (NAVSTAR-GPS) constella- tion has 24 satellites with 3 spares orbiting the earth at an altitude of about 12,600 miles (USNO NAVSTAR GPS, 2006; Longley et. al, 2005; Steede-Terry, 2000). The GLONASS consists of 21 satellites in 3 orbital planes, with 3 on-orbit spares (Space and Tech, 2005). The proposed system GALILEO will be based on a constellation of 30 satellites and ground stations (Europa, 2005). 279 Coupling GPS and GIS The NAVSTAR-GPS has three basic segments: (1) the space segment, which consists of the satel- lites; (2) the control segment, which is a network of earth-based tracking stations; and (3) the user segment, which represents the receivers that pick up signals from the satellites, process the signal data, and compute the receiver’s location, height, and time (Maantay and Ziegler, 2006; Lange and Gilbert, 2005). Data Limitations and Accuracy Level Besides the timing discrepancies between the satellites and the receivers, some other elements that reduce the accuracy of GPS data are orbit errors, system errors, the earth’s atmosphere, and receiver noise (Trimble, 2002; Ramadan, 1998). With better attention to interoperability between the GPS units, hardware, and software, some of these errors can be minimized before the data are used in GIS (Thurston et. al, 2003; Kennedy, 2002). Using a differential correction process, the receivers can correct such errors. The Differential GPS (DGPS) uses two receivers, one stationary and one roving. The stationary one, known as the base station, is placed at a precisely known geographic point, and the roving one is carried by the surveyor (Maantay and Ziegler, 2006; Imran et. al, 2006; Thurston et. al, 2003; Kennedy, 2002; Taylor et. al, 2001; Steede-Terry, 2000). The base station sends differential correction signals to the moving receiver. Prior to 2000, the GPS signal data that was available for free did not deliver horizontal po- sitional accuracies better than 100 meters. Data with high degree of accuracy was only available to U.S. government agencies and to some uni- versities. After the U.S. Department of Defense removed the restriction in May 2000, the positional accuracy of free satellite signal data increased to 15 meters (Maantay and Ziegler, 2006). In Sep- tember 2002, this accuracy was further increased to 1 to 2 meters horizontally and 2 to 3 meters vertically using a Federal Aviation Administration funded system known as Wide Area Augmenta- tion System (WAAS). WAAS is available to the public throughout most of the continental United States (Maantay and Ziegler, 2006). Depending on the receiver system, the DGPS can deliver positional accuracies of 1 meter or less and is used where high accuracy data is required (Maantay and Ziegler, 2006; Longley et. al, 2005; Lange and Gilbert, 2005; Taylor et. al, 2001). For example, the surveying professionals now use Carrier Phase Tracking, an application of DGPS, which returns positional accuracies down to as little as 10 centimeters (Maantay and Ziegler, 2006; Lange and Gilbert, 2005). Integr At Ion of gps And gIs The coupling of GPS and GIS can be explained by the following examples: • A el d crew can use a GPS receiver to enter the location of a power line pole in need of repair; show it as a point on a map displayed on a personal digital assistant (PDA) using software such as ArcPad from ESRI; enter attributes of the pole; and nally transmit this information to a central database (Maantay and Ziegler, 2006). • A re searcher may conduct a groundwater contamination study by collecting the co- ordinates and other attributes of the wells using a GPS; converting the data to GIS; measuring the water samples taken from the wells; and evaluating the water quality parameters (Nas and Berktay, 2006). There are many ways to integrate GPS data in GIS, ranging from creating new GIS features in the eld, transferring data from GPS receiv- ers to GIS, and conducting spatial analysis in the eld (Harrington, 2000a). More specically, the GPS-GIS integration can be done based on the 280 Coupling GPS and GIS following three categories – data-focused integra- tion, position-focused integration, and technol- ogy-focused integration (Harrington, 2000a). In data-focused integration, the GPS system collects and stores data, and then later, transfers data to a GIS. Again, data from GIS can be uploaded to GPS for update and maintenance. The posi- tion-focused integration consists of a complete GPS receiver that supplies a control application and a eld device application operating on the same device or separate devices. In the technol- ogy-focused integration, there is no need for a separate application of a device to control the GPS receiver; the control is archived from any third party software (Harrington, 2000a). Figure 1 provides an example of a schematic workow process of the GPS-GIS integration by using Trimble and ArcGIS software. In short, the integration of GPS and GIS is primarily focused on three areas - data acquisition, data processing and transfer, and data maintenance. Data Acquisition Before collecting any data, the user needs to de- termine what types of GPS techniques and tools will be required for a particular accuracy require- ment and budget. The user needs to develop or collect a GIS base data layer with correct spatial reference to which all new generated data will be referenced (Lange and Gilbert, 2005). The scale and datum of the base map are also important. For example, a large-scale base map should be used as a reference in a site specic project in order to avoid data inaccuracy. While collecting GPS data in an existing GIS, the datum designation, the projection and coordinate system designation, and the measurement units must be identical (Kennedy, 2002; Steede-Terry, 2000). It is recommended that all data should be collected and displayed in the most up-to-date datum avail- able (Lange and Gilbert, 2005). The user may create a data dictionary with the list of features and attributes to be recorded before going to the eld or on-spot. If it is created beforehand, the table is then transferred into the GPS data collection system. Before going to the eld, the user also needs to nd out whether the locations that will be targeted for data collection are free from obstructions. The receivers need a clear view of the sky and signals from at least four satellites in order to make reliable position measurement (Lange and Gilbert, 2005; Giaglis, 2005). In the eld, the user will check satellite availability and follow the manuals to congure GPS receivers before starting data collection. GIS uses point, line, and polygon features, and the data collection methods for these features are different from one another. A point feature (e.g., an electricity transmission pole) requires the user Figure 1. Example workow process of GPS-GIS integration 281 Coupling GPS and GIS to remain stationary at the location and capture the information using a GPS device. For a line feature (e.g., a road), the user needs to record the positions periodically as s/he moves along the feature in the real world. To capture a polygon feature (e.g., a parking lot) information, the posi- tions of the recorder are connected in order to form a polygon and the last position always connects back to the rst one. The user has to decide what types of features need to be created for a GIS map. In a small scale map, a university campus can be shown as a point, whereas in a detailed map, even a drain outlet can be shown as a polygon. GPS coordinates can be displayed in real time in some GIS software such as ESRI ArcPad, Intergraph Intelliwhere, and Terra Nova Map IT. In the age of mobile GIS, users can go on a eld trip, collect GPS data, edit, manipulate, and visualize those data, all in the eld. While GPS and GIS are linked, the GPS receiver can be treated as the cursor of a digitizer. It is linked to the GIS through a software module similar to a digitizer controller where data are saved into a GIS ling system (Ramadan, 1998; UN Statistics Division, 2004). In real-time GPS/GIS integration, data may be collected and stored immediately for future use in a mapping application, or data may be discarded after use in a navigation or tracking application (Thurston et. al, 2003). For example, Map IT is a new GIS software designed for digital mapping and GPS data capture with a tablet PC. The software connects a tablet pc to a GPS antenna via a USB port. While conduct- ing the eld work, the user may use the software to: (a) display the current ground position on the tablet PC’s map display in real time; (b) create new features and add coordinates and other attributes; (c) edit or post-process the data in real time; and (d) automatically link all activity recorded in the eld (including photographs, notes, spreadsheets, and drawings) to the respective geographic posi- tions (Donatis and Bruciatelli, 2006). Although the integration of GIS and GPS can in general increase accuracy and decrease project costs and completion time, it can also create new problems, including creation of inaccurate data points and missing data points (Imran et. al, 2006). Sometimes a handheld GPS navigator may not be able to acquire a lock on available satellites because of natural conditions like dense forest canopies, or human-made structures like tall buildings or other obstacles (Lange and Gilbert, 2005; Thurston et. al, 2003). Data collection with GPS also might get affected by any equipment malfunction in the eld. data processing and t ransfer Once the data are collected, they can be download- ed, post-processed, and exported to GIS format from the eld computer to the ofce computer. Where real-time signals are needed but cannot be received, the post-processing techniques can be applied to re-process the GPS positions. Us- ing this technique, the feature positions can be differentially corrected to the highest level of accuracy. The users who integrate GPS data into their own applications need to consider how and when they should apply differential corrections. Real-time processing allows recording and correcting a location in seconds or less, but is usually less accurate. Post-processing allows the surveyor recording a location as much time as s/he likes, and then differentially corrects each location back in the ofce. This technique is used in mapping or surveying (Steede-Terry, 2000; Thurston et. al, 2003). Instead of relying on real-time DGPS alone, the users should enable their applications to record raw GPS data and al- low post-processing techniques to be used either solely or in conjunction with real-time DGPS (Harrington, 2000b). Most GPS receiver manufacturers have their own data le format. GPS data is stored in a receiver in its own format and later can be trans- lated to various GIS formats (Lange and Gilbert, 282 Coupling GPS and GIS 2005; Ramadan, 1998). Data can be transferred in a couple of ways. One simple way is collecting coordinates and attributes in a comma delimited le from the GPS device storage. The other more preferable way is converting the data from GPS storage to the user-specic database interchange format using a data translation program (Lange and Gilbert, 2005). Such a program allows the user to (1) generate metadata; (2) transform the coordinates to the projection, coordinate system, and datum of the user’s choice; and (3) translate GPS data into customized formats that the GPS manufacturers could never have anticipated (Lange and Gilbert, 2005). A number of le interchange protocols are available to exchange data between different brands and types of receivers. One widely used interchange protocol is the Receiver Independent Exchange Format (RINEX), which is supported by most satellite data processing software (Yan, 2006). Another commonly used interface standard is a standard released by the National Marine Electronics Association (NMEA). Most GPS receivers support this protocol and can output NMEA messages, which are available in ASCII format (Yan, 2006). data Maintenance For data revisions or data maintenance, GIS data is transferred back to the eld computer and can be veried or updated in the eld. The user can relocate features via navigation, verify the position and attribute features, and navigate to locations to collect new attribute data. The user may select features and examine them in the eld, modify attributes, and even collect new features if desired. Using receivers such as Trimble, any feature that has been added or updated is automatically marked to determine which data needs to go back to GIS (Trimble, 2002). future trends The future trends of GIS-GPS integration will be focused on data accuracy, interoperability, and affordability. In order to make the WAAS level of precision available to users worldwide, the Unites States is working on international agreements to share similar technologies avail- able in other parts of the world, namely Japan’s Multi-Functional Satellite Augmentation System (MSAS) and Europe’s Euro Geostationary Navi- gation Overlay Service (EGNOS) (Maantay and Ziegler, 2006). In addition, the European satellite positioning system, Galileo, will be dedicated to civilian activities which will further increase the availability of accurate data to general users. New applications of GIS-GPS integration are constantly becoming popular and widespread. The latest developments in GPS technology should encourage more use of such integration in the future. Reduction in cost and personnel training time of using GPS technology with high data accuracy will eventually provide a cost-effective means of verifying and updating real time GIS mapping in the eld (Maantay and Ziegler, 2006; UN Statistics Division, 2004). conc Lus Ion In today’s market, the mobile GIS and GPS devices are available with greater accuracy at a reduced cost. The data transfer process from GPS to GIS has become faster and easier. GIS software is get- ting more powerful and user friendly, and GPS devices are increasingly getting more accurate and affordable. The integration of GIS and GPS has been already proven to be very inuential in spatial data management, and it will have steady growth in the future. 283 Coupling GPS and GIS references Donatis, M., & Bruciatelli, L. (2006). Map IT: The GIS Software for Field Mapping with Tablet PC. Computers and Geosciences, 32(5), 673-680. Europa web site. http://www.eu.int/comm/dgs/en- ergy_transport/galileo /index_en.htm, accessed on December 12, 2005 Giaglis, G. (2005). Mobile Location Services. In M. Khosrow-Pour (Ed.), Encyclopedia of Infor- mation Science and Technology, 4, 1973-1977. Pennsylvania: Idea Group Reference. Harrington, A. (2000a). GIS and GPS: Technolo- gies that Work Well Together. Proceedings in the ESRI User Conference, San Diego, California. Harrington, A. (2000b). GPS/GIS Integration: What Can You Do When Real-Time DGPS Doesn’t Work? GeoWorld, 13(4). Available online at http:// www.geoplace.com/gw/2000/0400/0400int.asp, accessed on August 25, 2006. Imran, M., Hassan, Y., & Patterson, D. (2006). GPS-GIS-Based Procedure for Tracking Vehicle Path on Horizontal Alignments. Computer-Aided Civil and Infrastructure Engineering, 21(5), 383-394. Kennedy, M. (2002). The Global Positioning System and GIS: An Introduction. New York: Taylor and Francis. Maantay, J. & Ziegler, J. (2006). GIS for the Urban Environment. California: ESRI Press, 306-307. Nas, B. & Berktay, A. (2006). Groundwater Contamination by Nitrates in the City of Konya, (Turkey): A GIS Perspective. Journal of Environ- mental Management. 79(1), 30-37. Lange, A. & Gilbert, C. (2005). Using GPS for GIS Data Capture. In Geographic Information Systems: Principles, Techniques, Management, and Applications (pp. 467-476). NJ: John Wiley & Sons, Inc. Letham, L. (2001). GPS Made Easy. Washington: The Mountaineers, 5(12), 183-186. Longley, P., Goodchild, M., Maguire, D., & Rhind, D. (2005). Geographic Information Systems and Science. New Jersey: John Wiley & Sons, Inc. (pp. 122-123, 172-173). Ramadan, K. (1998). The Use of GPS for GIS Applications. Proceedings in the Geographic Information Systems: Information Infrastructures and Interoperability for the 21st Century Informa- tion Society, Czech Republic. Space and Tech web site. http://www.spacean- dtech.com/spacedata/constellations/glonass_con- sum.shtml, accessed on December 12, 2005 Steede-Terry, K. (2000). Integrating GIS and the Global Positioning System. California: ESRI Press. Taylor, G., Steup, D., Car, A., Blewitt, G., & Corbett, S. (2001). Road Reduction Filtering for GPS-GIS Navigation. Transactions in GIS, 5(3), 193-207. Thurston, J., Poiker, T., & Moore, J. (2003). In- tegrated Geospatial Technologies – A Guide to GPS, GIS, and Data Logging. New Jersey: John Wiley & Sons, Inc. Trimble Navigation Limited. (2002). TerraSync Software – Trimble’s Productive Data Collection and Maintenance Tool for Quality GIS Data. California: Trimble Navigation Limited. UN Statistics Division. (2004). Integration of GPS, Digital Imagery and GIS with Census Mapping. New York: United Nations Secretariat. USNO NAVSTAR GPS web site. http://tycho. usno.navy.mil/gpsinfo.html, accessed on August 26, 2006. Yan, T. (2006). GNSS Data Protocols: Choice and Implementation. Proceedings in the International Global Navigation Satellite Systems Society IG- NSS Symposium, Australia. 284 Coupling GPS and GIS key t er Ms Coordinate System: A reference framework used to dene the positions of points in space in either two or three dimensions. Datum: The reference specications of a measurement system, usually a system of coor- dinate positions on a surface or heights above or below a surface. DGPS: The Differential GPS (DGPS) is used to correct GPS signal data errors, using two receiv- ers, one stationary (placed at a precisely known geographic point) and one roving (carried by the surveyor). The stationary receiver sends differ- ential correction signals to the roving one. GPS Segment: GPS consists of three seg- ments: (i) space segment – the GPS satellites, (ii) user segment – the GPS handheld navigator, and (iii) ground control segment – the GPS monitor- ing stations. Projection: A method requiring a system- atic mathematical transformation by which the curved surface of the earth is portrayed on a at surface. Scale: The ratio between a distance or area on a map and the corresponding distance or area on the ground, commonly expressed as a frac- tion or ratio. WAAS: The Wide Area Augmentation System (WAAS) is a system that can increase the GPS signal data accuracy to 1 to 2 meters horizontally and 2 to 3 meters vertically. 285 Chapter XXXVI Modern Navigation Systems and Related Spatial Query Wei-Shinn Ku Auburn University, USA Haojun Wang University of Southern California, USA Roger Zimmermann National University of Singapore, Singapore Copyright © 2009, IGI Global, distributing in print or electronic forms without written permission of IGI Global is prohibited. Abstr Act With the availability and accuracy of satellite-based positioning systems and the growing computational power of mobile devices, recent research and commercial products of navigation systems are focusing on incorporating real-time information for supporting various applications. In addition, for routing purposes, navigation systems implement many algorithms related to path nding (e.g., shortest path search algorithms). This chapter presents the foundation and state-of-the-art development of navigation systems and reviews several spatial query related algorithms. Introduct Ion Navigation systems have been of growing interest in both industry and academia in recent years. The foundation of navigation systems is based on the concept of utilizing radio time signals sent from some wide-range transmitters to enable mobile receivers to determine their exact geographic [...]... org/html.charters/geopriv-charter.html the 36th Annual Hawaii International Conference on System Sciences (HICSS’03) Iqbal, M.U., & Lim, S (2006) A privacy preserving GPS-based Pay-as-You-Drive insurance scheme Symposium on GPS/GNSS (IGNSS2006), Surfers Paradise, Australia, 1 7- 2 1 July, 2006 US-Department -of- Transportation (19 97) A Report to Congress: Nontechnical Constraints and Barriers to the Implementation of Intelligent... position on digital maps As of 2006, the Global Positioning System (GPS) is the only fully functional satellite-based positioning signal transmission system Global Positioning System The invention of GPS has had a huge influence on modern navigation systems GPS was developed by the U.S Department of Defense in the mid-1980s Since it became fully functional in 1994, GPS has acted as the backbone of modern... applications can be quietly running at all times, passing on real-time information of the vehicle’s movements such as Global Positioning System (GPS) enabled Pay-As-You-Drive (PAYD) insurance (Grush, 2005) Although location data is critical to the operation of such applications, there is a precarious balance between the necessary dissemination of location information and the potential for abuse of this... International Conference on Mobile Systems, Applications, and Services Gruteser, M., & Hoh, B (2005) On the Anonymity of Periodic Location Samples Paper presented at the 2nd International Conference on Security in Pervasive Computing, Boppard, Germany Drane, C., & Rizos, C (19 97) Role of Positioning Systems in ITS In Positioning Systems in Intelligent Transportation Systems (pp 29 8-2 99) Boston: Artech... discussion of possible privacy-strengthening measures Copyright © 2009, IGI Global, distributing in print or electronic forms without written permission of IGI Global is prohibited Location Privacy in Automotive Telematics INTRODUCT ION The proliferation of location-aware computing devices promises an array of “quality -of- life enhancing” applications These services include in-car navigation, roadside... Y., Quddus, M A., & Noland, R B (2004) Integrated positioning algorithms for transport telematics applications In proceedings of the Institute of Navigation (ION) annual conference, 2 0-2 4 September, California, USA Phuyal, B (2002) Method and use of aggregated dead reckoning sensor and GPS data for map matching In proceedings of the Institute of Navigation (ION) annual conference, 2 0-2 7 September, Portland,... based on the context, in telematics perspective, location is a context for customization Electronic Tolls: Electronic payment systems designed to identify an electronic tag mounted on a vehicle to deduct the toll charges electronically from the vehicle owner’s account In-Car Navigation: Usually a voice-activated system with a liquid crystal display (LCD) screen displaying maps and a combination of on- board... reliability of the positioning solution REFERENCES Greenfeld, J S (2002) Matching GPS observations to locations on a digital map In proceedings of the 81st Annual Meeting of the Transportation Research Board, January, Washington D.C Fu, M., Li, J., & Wang, M (2004) A hybrid map matching algorithm based on fuzzy comprehensive Judgment, IEEE Proceedings on Intelligent Transportation Systems, 61 3-6 17 Honey,... strengthen location privacy Ba ckground Before delving into the core issue of location privacy, it is important to agree on a definition of privacy itself Much of the literature pertaining to privacy refers to Westin’s precise definition In the context of telematics, location privacy is a special case of privacy, relating to the privacy of location information of the vehicle, and ultimately the user of the vehicle... Hong, J., & Gruteser, M (2003) Wireless Location Privacy Protection IEEE Computer Magazine, 36(12), 13 5-1 37 Snekkenes, E (2001) Concepts for personal location privacy policies Paper presented at the Proceedings of the 3rd ACM conference on Electronic Commerce, Tampa, Florida, USA Standards-Australia (2000) AS 472 1-2 000: Personal privacy practices for the electronic tolling industry: Standards Australia . Europe and Japan, respectively. They can be regarded as variants of WAAS. The Local Area Augmentation System (LAAS) (United States Department of Transportation, FAA, 2002) uses a similar approach. displayed on a personal digital assistant (PDA) using software such as ArcPad from ESRI; enter attributes of the pole; and nally transmit this information to a central database (Maantay and. proliferation of location-aware computing devices promises an array of “quality -of- life enhancing” applications. These services include in-car navigation, roadside assistance, infotain- ment,