A geographical information system (GIS) is a system for collecting, analyzing and managing spatially related data. It allows users to search for information that has a geographical connection, such as a list of restaurants in a given area.
A specific type of GIS is virtual globe, a 3-D technology used to view the Earth from a variety of angles and positions. Its uses are diverse and range from simple geographical studies to environmental tracking, to route information and demographic analysis.
Virtual globe applications are enhancing their value by adding the option of using high-resolution images instead of computer-generated approximations. Users can access satellite imagery to view the Earth in great detail and can search for information, such as the location of schools and hospitals, that has a geographical connection.
GIS is increasing being used to provide location-based services (LBS), which allow mobile devices enabled with global positioning systems (GPS) to display their location in relation to other places, including fixed assets like restaurants, gas stations and police stations, or mobile assets like friends, children, and transportation services, or to relay their position back to a main server for processing.
The most popular GIS applications today include Google Earth, NASA's World Wind, and Microsoft Virtual Earth. Google Earth and MS Virtual Earth 3D are accessible from a standard web browser and are free to use, although World Wind is the only application in the public domain and is not copyrighted. Google Earth and Virtual Earth allow personal use of their images free of cost but involve a fee for commercial use.
Legal Issues
Privacy
With a spatial database, it is possible to locate data that has location significance. For example, if someone knew your home address, using a spatial database he could query the locations of the ATMs closest to your location, and surmise that you would likely use one of them frequently.Most land areas are covered by satellite imagery with a resolution of about 15 m per pixel, and some population centers are also covered by aircraft imagery with several pixels per meter. With the resolution becoming finer and finer, many concerns are raised about the technology intruding into the privacy of individuals and countries. Although Google Earth has worked with a number of countries to blur buildings with a national security interest, the masking of images of personal property has met with significantly less success, primarily because of the relatively low resolution involved. This topic is a popular discussion on a number of blogs.
References
- Google is watching
(Jeffry Veen) - Google Earth Privacy and Security Roundup (The Map Room)
- Google satellite imagery raises terrorism concerns (GovernmentExecutive.com)
Print view
Email to a friend
Submit to Reddit
Save to del.icio.us
Submit to Digg.com
Stumble It!