Waypoint
From Free net encyclopedia
A waypoint is a mapped reference travelers can easily identify on the ground and use to verify their location. Waypoints may include natural rock formations, springs, oasis, or other permanent terrain feature.
A waypoint may also be considered a fixed location with a specified longitude and latitude and UTM coordinates, which is maintained by a global positioning system (GPS). Waypoints mark a destination, a point along the way to a destination, or a point of reference. GPSs can record a waypoint on the spot to within 3 meters or better using a GPS unit with Wide Area Augmentation System (WAAS) capability. Waypoints can also be marked on a computer mapping program and uploaded to the GPS, marked on the GPS's own internal map, or entered manually on the device as a pair of coordinates.
If the GPS unit has track-logging capabilities, one can also define waypoints after the fact from where one has been. Marine GPS units often have a special "Man Overboard" key, which instantly defines the boat's position at that moment as a waypoint and then begins displaying the distance and course back to that position.
In navigating with a GPS, a "route" normally consists of one or more waypoints. To traverse a route, the GPS user navigates to the nearest waypoint, then to the next one in turn until the destination is reached. Most units have the ability to compute a great circle route towards a waypoint, enabling them to find the shortest route even over long distances.
Many GPS units, both military and civilian, now offer integrated cartographic databases (also known as base maps), allowing users to locate a destination on a map and define it as a waypoint. Some GPS systems intended for automobile navigation can generate a suggested driving route between two waypoints, based on the cartographic database. As one drives along the route, the system indicates the driver's current location and gives advance notice of upcoming turns. The best of these systems can take into account traffic restrictions such as one-way streets and intersections where left turns (or, in the UK, right turns) are prohibited when computing the suggested driving route.
Most GPS units allow the user to assign a name to each waypoint. Many models also let the user select a symbol to identify the waypoint on a graphical map display from a built-in library of icons. These include standard map symbols for marine navigation aids such as buoys, as well as such land-based symbols as treasure chests, churches, bridges, shopping centers, parks, and tunnels.Template:Tech-stub