GPS for Dummies.pdf - Engineering Surveyor

Chapter 20Overhead Image Web SitesIn This Chapter Discovering aerial photos and satellite images Finding photos with TerraServer-USA Using TerraServer.com Exploring cities with GlobeXplorerAlthough many Internet users know about street mapping Web sites likeMapQuest (see Chapter 18), fewer people are aware of Web sites thatprovide free aerial photos (taken from aircraft) and satellite data. Theseimages complement traditional maps, displaying features that don’t show upon topographic or street maps, such as vegetation and unmarked roads ortrails. In addition, aerial photos and satellite images are often more up-to-datethan topographic maps and provide more timely and accurate information.In this chapter, I present several popular Web sites that you can visit to viewaerial photos and satellite images; I also describe the basics of using three ofmy favorite aerial photo and satellite services.I treat both aerial photos and satellite images as simply graphics images inthis chapter because that’s how you view them on the Web. Unless there’s aneed to specifically differentiate between an aerial photo and a satelliteimage, the word image in this chapter refers to both.Using Web Aerial and Satellite ImagesOne of the biggest advantages to using an image captured from an airplane orsatellite is that it shows reality — not a cartographer’s representation drawnon a map. You can use aerial and satellite images to Complement a topographic map to help determine your currentlocation. Find roads and trails not shown on maps.