GPS for Dummies.pdf - Engineering Surveyor

312Part IV: Using Web-hosted Mapping ServicesWhen it comes to commercial topographic map Web sites, you’re paying forconvenience in accessing and using the maps online as well as having anumber of different types of maps available in a single place. Although someof the same services are available for free elsewhere on the Internet, commercialmap Web sites are priced reasonably enough that you can try them tosee whether they meet your needs.These popular commercial map sites, along with some screenshots, give youan idea of what it’s like to use the online maps with your browser.TopoZoneTopoZone, the first interactive Web mapping site on the Internet, provides acomprehensive collection of digital topographic maps and aerial photos forthe United States. Any Internet user can freely search for and view USGStopographic maps; a screenshot of accessing a map with TopoZone is shownin Figure 19-6. For a yearly subscription fee of under $50, the TopoZone Proservice offers access to aerial photos, street maps, downloading USGS DigitalRaster Graphics map, and other enhanced features. To read more aboutTopoZone, go to www.topozone.com.Figure 19-6:UseTopoZone toview a Webtopographicmap.