Most GPS receivers function with a battery. However, GPS receivers powered by cells are also available. More often than not, a base map is fed into the memory of a GPS that elaborates basic geography of the area and is not a very well detailed map in general. Other sets that are not fed with a base map still display such useful information as the speed of traveling of the user, the distance he has covered from the starting point since the time he moved as well as the distance that remains to be covered to reach the point of destination. Besides, such sets also tell the orientation of the user with respect to a specific direction up to a maximum angle of 360 degrees.
A GPS informs the user about the exact time and determines the accurate location wherever it is taken in the world irrespective of the weather condition and the time of the day. Information about the location essentially constitutes the longitude, latitude and the altitude of the place with respect to the mean sea level. That is the reason why the location determined by a GPS is referred to as three dimensional in nature. GPS functions both on Earth and in space. Today, such GPSs have been developed that can even function under water. Waterproof GPSs are easily available in the market. The base map stored in the memory of a GPS makes it very easy for the user to realize his location with respect to his starting point and the destination. The best characteristic feature of some of the most modern GPSs is that they can be connected to a computer with the help of a connecting cable and also via Bluetooth or infra-red. This is principally one of the most useful qualities of a GPS since it not only saves time, papers and effort put in saving destination coordinates in a GPS, but also substantially reduces the chance of occurrence of manual error that become significant in case the coordinates are saved manually. By