Virtual Globes
We have come a long way since the first globe made by Martin Behaim in 1492, which contained fabulous references to contemporary beliefs and superstitions about what lay beyond the edges of the known world.
Today's globes incorporate the latest geo-positioning data received directly from satellites, and sometimes they are not even physical objects.
That's right, with the advent and improvement of software 3-d modeling, actual physical globes that you can take up in your hands seem to have become passé.
The newest globes are virtual globes that exist only in cyberspace, and go out of existence as soon as you turn off that electronic screen or shut down the computer. Virtual globes take the movement begun by digital globes and take it one step further. They not only do away with actual colors and texts, but are also able to dispense with the physical medium underlying the pictures and the text.
Virtual globes take advantage of computer technology that is able to visually simulate a three-dimensional object in real space. They often use OpenGL® or some equivalent 3-d rendering and visualization techniques to achieve this. The database underlying the display is connected to some global repository of geographical information, which in some cases can be sophisticated GIS (Geographic Information System) databases. There is often a direct correspondence between such a database and the display of the virtual globe, so that the latest changes can be reflected directly and without any delay.
The shapes of continents, rivers, mountains, lakes and oceans change only on a geological time scale, at a magnitude of millions of years. None of these change fast enough to make it necessary to maintain a connection with a database so that the display can be updated in real time. So what is the logic behind taking all this trouble?
The truth is that with the coming of virtual globes, the display of geographical data no longer needs to be static, showing one thing only. The face of a virtual globe can easily change to zoom in and out, show weather information from the latest geo-stationary satellite data, depict the flow and movement of winds, currents and storms, and magnify the display to such levels that traffic information can be mapped on to it. You can rotate the sphere with virtual 'hands' to choose your target area, and then zoom in hundreds and thousands of times to locate even your own hometown, the street you live in, or if you're lucky maybe even your own house!
This is a long way that we've come from the the first globe of Martin Behaim, and surely it justifies the use of GIS data and GPS (Global Positioning System) devices.
Virtual globes are available as software programs, and there are more than one offering in the market. Microsoft Inc. has two such, the more famous of them being called MapPoint®. While many other mapping software programs have been based on flat maps, MapPoint® uses three-dimensional concepts, and can be called the most successful virtual globe program in existence at present. There is another virtual globe product that Microsoft has included with their Encarta suite.
There are also available some excellent and free online virtual globe programs, including those offered by NASA. This is known as NASA World Wind. There was a program called Keyhole, which has recently been taken over by Google, Inc. and renamed Google Earth.
There are also some websites that offer virtual globes online, and these are created with an Internet graphical technology known as VRML. To use or view a VRML application, you need to install a VRML plug-in for your browser.
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