GPS for Dummies.pdf - Engineering Surveyor

290Part IV: Using Web-hosted Mapping ServicesMap sites use geocoding to locate addresses, which means that latitude andlongitude coordinates are assigned a street address. These coordinates arethen passed to the map database to retrieve a map or driving directions.Listing common streetmap Web site featuresYou can find quite a few street map Web sites on the Internet, and they generallyall have the same features in common, including Map display: Obviously, street map sites have street maps. Streets androads are displayed in vector maps (created with lines and shapes)instead of raster maps (scanned versions of paper maps). Vector mapsare faster and efficient to display. You can zoom in and out on the mapsto view them in different scales. Address searches: To display a map, you enter a street address, city,state, or ZIP code. The map Web site checks the location informationthat you entered to see whether it’s valid; if it is, the map is displayed. Route creation: In addition to showing a map of a single location, streetmap Web sites can also create routes that show you how to get fromPoint A to Point B. Just enter a starting and ending address, and the Website will display a map of how to get to your destination. Route directions: Street map Web sites also can provide you with drivingdirections for getting to a location. The directions list streets, turns,and estimated times and distances for traveling between different partsof the route. Printing: All street map Web sites can output maps and driving directionsto your printer, which is usually easier than lugging your PC withyou on a trip.Street map Web site companies usually don’t make their own maps but relyon map data licensed from one or more third-party map companies such asGeographic Data Technology (GDT), NAVTECH, and TeleAtlas. Although mapWeb sites might use the same data, their maps can look different dependingon how they display and use the data.Web versus PC software street mapsIf you’ve read Chapter 12 (all about PC street-navigation programs), youmight be wondering whether you should use a Web-hosted street map or aprogram that comes bundled with a street map CD-ROM. Both can findaddresses, display street maps, and create routes. To answer your question,look at the advantages and disadvantages to using street map Web sites comparedwith their PC program cousins.