Waypoint

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A waypoint is any mapped reference point useful for pilotage, which navigators can identify on land or at sea to verify their location. Natural waypoints may include natural rock formations, springs and oasis. Artificial waypoints may include buoys, lighthouses and radio beacons.

A waypoint may also be considered a fixed location with a specified longitude and latitude or UTM coordinates, which is maintained by a radio navigation system receiver such as a GPS set. A waypoint can be a destination, a location of a course change along a journey, or a point of reference useful for navigation. A GPS receiver can record a waypoint at its current location to an accuracy of within 3 meters or better if using Wide Area Augmentation System (WAAS) capability. Waypoints can also be marked on a computer mapping program and uploaded to the GPS receiver, marked on the receiver's own internal map, or entered manually on the device as a pair of coordinates.

If the GPS receiver has track-logging capabilities, one can also define waypoints after the fact from where one has been. Marine GPS receivers often have a "Man Overboard" key, which instantly creates a waypoint in the receiver for the boat's position at that moment and then begins displaying the distance and course back to that position.

In navigating with 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 receivers 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 receivers, both military and civilian, now offer integrated cartographic databases (also known as base maps), allowing users to locate a point 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 receivers 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, marinas and anchorages, as well as such land-based symbols as churches, bridges, shopping centers, parks, and tunnels.

In simulations of Mobile ad-hoc networks the Random Waypoint mobility model is the one most often used

Waypoint

See also