What is Google Earth?
When Keyhole Inc. first developed their virtual globe in 2001, it was distributed under the name Earth Viewer and enjoyed modest success (Tuttle, Anderson, & Huff 2008). However, it was only after Google, the international Internet-search giant, purchased the company in 2004 and restructured it then rebranded it as Google Earth in 2005 that it became an international sensation. By 2008 Google Earth had collected over 400 million downloads (Jones 2008).
Google Earth is a virtual globe that uses satellite imagery and terrain data to digitally model the world. It seamlessly stitches together millions of pictures of the Earth and overlays them on top of a landscape that accurately represents the hills, valleys, and plains of the globe (Google Earth). The satellite images that Google incorporates are no older than three years but, under normal circumstances, no more recent than six months. Most of these satellite images have a resolution of about 15 meters per pixel—good enough to define houses, buildings, and terrain features. In more urban areas, imagery can be as good as one to three meters per pixel (Wikipedia 2011). At this resolution, it is not difficult to pick out cars or individuals. However, in some places such as rural towns and deserts, the resolution can be as poor as 500 meters per pixel since it is assumed that few users will want to examine those areas very closely (Wikipedia 2011).
Google Earth is considered very easy to use relative to other virtual globes because of its straightforward user interface. The program easily allows users to zoom, pan, and even tilt the perspective of the imagery in order to get a better view of the area simply by clicking and dragging on the image or scrolling up and down (Google Earth). It also allows users to search for a location by typing in an address or, for many famous landmarks like Disney World, just typing the place’s name.
In addition to offering access to a digitally modeled globe, Google Earth also includes many features that augment this functionality further called layers and KMLs. Layers, which are included with the program, and KMLs, which can be downloaded and turned on in less than a minute, are information overlays that are placed on top of the virtual globe in order to enhance the experience. Different layers visually provide information on different topics from humanitarian aid to seismic activity to college sports and everything in between.
Tuttle, B., Anderson, S. & Huff, R. (2008). Virtual globes: history, use, and future. Geography Compass 2(5), 1478-1505.
Jones, M. (2008). Keynote Speaker, Michael Jones – GeoWeb 2008 [video file]. Video posted to http://www.youtube.com/watch?v=U5SYg2bRyD0
Wikipedia. (2011). Google Earth. Wikipedia, The Free Encyclopedia. Retrieved from http://en.wikipedia.org/w/index.php?title=Google_Earth&oldid=422882042