How Google Earth Works ??

Google Earth - Almost everyone of us is familiar with it .. we ve seen the satellite imageries of our college(SSNCE), !! and perhaps somebody of you could have had a pretty good look at their house even .. in google earth !!(How many ve seen ur house in google earth ??).Well , ever wondered how all these are possible .. ?? and how these work ?? (Nope ??) . Then , plunge into this article before something more attractive in the web distracts you ..(Yeah,i get distracted too much . My level of distraction in web is well above the observed limits of normal people .. Sounds too much ?? ) ..

Google Earth is currently available for download as a desktop application, although you need to be connected to the Internet to use it. Every time you open Google Earth, it automatically connects to Google's servers, giving you access to terabytes of geographical, political and social data. For instance, you can view a city with certain "layers" turned on, including topographical information, population data and crime statistics for the area. The layers and all of the map navigation buttons, including zoom, tilt and rotate, are all located in the Google Earth frame.

Google Earth comprises an array of features that would probably take months to fully utilize, the basic features fit loosely into the following categories:
Mapping/directions
Local search
Sightseeing

Let's find out where Google Earth gets its data.

Google Earth was once a premium program called Keyhole that cost about $90. When Google purchased Keyhole, it inherited terabytes of digital mapping data and set about creating a basic version of the software that would be available for free download. Now you're all caught up.

The photographic maps available on Google Earth come primarily from two sources: satellites and aircraft. Google gets this imagery and other digital mapping information from sources such as TeleAtlas and EarthSat, both of which compile photographs and maps into digital form for commercial applications. Because the data comes from different sources, it's provided at different resolutions, which is why some areas of the globe appear crisp even at street level while others are blurry from a great distance. Google is striving to have as much high definition coverage of the world as possible. When you use Google Earth, you're not viewing the imagery in real-time: according to Google, the information is no more than three years old and is continually updated as new data becomes available.

Google Earth has several countries like the United States, Canada and the United Kingdom covered to street level, meaning you can zoom in and view road names and local businesses and get directions from here to there. The database has a good amount of information on other regions like Western Europe, India and Japan as well, but the rest of the world is hit or miss. While you can zoom in and get a pretty good look at the Egyptian pyramids, you can't see street names or find a grocery store in the area. Google is constantly adding more information to its databases, though, and the maps are getting better with each update.

This brings us to another source of Google Earth's data: the Google search engine. Part of what makes Google Earth so addictive is its collaboration with Google search. When you're viewing a city, you can search for coffee shops, restaurants, grocery stores, bars and tons of other businesses in the vicinity, and you can click on them to get detailed information from the Google search engine. Users can also add a business location to a map by clicking on "Add/Edit a Business Listing" in the Google Earth toolbar.

Authors : Julia Layton and Jonathan Strickland