What is a GPS?
Photographs, satellite imagery, surface and subsurface scientific exploration and other means of gathering data have changed the way modern maps are constructed. Recent computer technologies have allowed for the development of Geographic Information Systems which provide complex pictures of the earth - both on the surface and beneath it. The global address of any place on earth includes both latitude and longitude. This coordinate system is widely used in all areas of navigation and related technologies. An example is Global Positioning System technology which uses a receiver to transmit a signal to satellites orbiting the earth. The GPS unit then uses the amount of time it takes for the satellite to receive its signal, and the satellite's' position in the sky to calculate an exact latitude and longitude.