accurately portray roads as they actually appear to give "life-like experiences." Functionality and Use Computer applications Proprietary and non-proprietary computer programs and applications provide imagery and street-level map data for much of the world. Scientific applications The development of mobile computing (PDAs, tablet PCs, laptops, etc.) has recently (since about 2000) spurred the use of digital mapping in the sciences and applied sciences. , science fields that use digital mapping technology include geology (see Digital geologic mapping), engineering, architecture, land surveying, mining, forestry, environmental, and archaeology. GPS navigation systems The principal use by which digital mapping has grown in the past decade has been its connection to Global Positioning System (GPS) technology. GPS is the foundation behind digital mapping navigation systems. How it works The coordinates and position as well as atomic time obtained by a terrestrial GPS receiver from GPS satellites orbiting Earth interact together to provide the digital mapping programming with points of origin in addition to the destination points needed to calculate distance. This information is then analyzed and compiled to create a map that provides the easiest and most efficient way to reach a destination. More technically speaking, the device operates in the following manner: GPS receivers collect data from at least four GPS satellites orbiting the Earth, calculating position in three dimensions. The GPS receiver then utilizes position to provide GPS coordinates, or exact points of latitudinal and longitudinal direction from GPS satellites. The points, or coordinates, output an accurate range between approximately "10-20 meters" of the actual location. The beginning point, entered via GPS coordinates, and the ending point, (address or coordinates) input by the user, are then entered into the digital mapping software. The mapping software outputs a real-time visual representation of the route. The map then moves along the path of the driver. If the driver drifts from the designated route, the navigation system will use the current coordinates to recalculate a route to the destination location. See also Cartography Digital elevation model Geographic information systems Digital architecture Digital geologic mapping Simultaneous localization and mapping Sound map References Digital mapping Geodesy