The term waypoint , abbreviated WP ( waypoint ), is used in geodesy and in navigation devices that can store multiple positions. A waypoint is an (electronic) mark that stores a unique position on earth. In addition to the coordinates ( latitude and longitude ), other information is usually also saved; z. B. the height or the quality of the coordinate. A waypoint can be given a name and a symbol. In aviation, waypoints are called intersections .
“Creating a waypoint” is also known as “setting a waypoint”. A waypoint is set to mark or remember the position of a certain location, e.g. B. the location of the car when hiking. Further waypoints can be determined by waypoint projection .
Routes are created from several waypoints or a waypoint list.
A track log is the set of many points that depict the course of a distance covered.
Waypoints can be saved in GPX format , for example .
Waypoints can serve as a destination. With the GPS device you can display the direction to the waypoint and the distance. With the autopilot , for example, you can automatically drive a ship to the waypoint.
In aviation, waypoints are used to define departure and arrival routes ( SIDs , STARs ) and airways . A waypoint can be a radio navigation aid ( VOR , NDB ) itself, by means of which radio navigation aids are defined in the region ( intersection ) or it can be determined by mere coordinates . Depending on the equipment of the aircraft, a waypoint can be navigated differently. The waypoint NEGRA in the picture can e.g. B. be approached as follows:
- Standard equipment: The aircraft flies with a heading of 267 ° towards VOR TRASADINGEN . When ZURICH EAST crosses the 66 ° radial , the waypoint has been reached.
- with the help of the DME ( distance measurement ): The aircraft flies with a heading of 267 ° towards the VOR-DME TRASADINGEN . The waypoint is reached at a distance of 40.2 NM from the VOR-DME.
- With GPS ( area navigation , RNAV ): The aircraft can approach the waypoint from any starting point.
The first two examples require a defined starting position, i. H. the waypoint cannot be approached from any starting point. With area navigation (RNAV), the coordinates of the waypoint and the aircraft are known and direct access from any point is possible.
Waypoints are published by the air traffic control of the respective country. In principle, however, all points that can be defined as above are suitable as waypoints. Any waypoints can be programmed with the help of the area navigation and the radio navigation aids are no longer required or are only required for comparison. In modern flight management systems , all waypoints are already saved with names and coordinates, so that they can be quickly integrated into the flight plan by entering the name ( NEGRA in the example above ).
When approaching a waypoint, the course to the next point is usually turned a few kilometers before the waypoint ( fly-by waypoint). This prevents overshooting the planned route, which would make subsequent course corrections necessary. If you want to fly over the point, it is called an overfly waypoint.
In the maritime waypoints are used to plan a route and to drive. The waypoints are in open water with sufficient water depth for the ship. They are set in such a way that obstacles can be avoided safely and wind, currents and swell are used optimally. Depending on the wind and weather forecast, the route is also changed while driving. The last waypoint of a route is usually in front of a port entrance, for example next to a control buoy .
A complete route is described in a waypoint list . The individual sections contain the coordinate of the previous waypoint, the course to be steered and the direct distance to the next waypoint, as well as its coordinate. In seafaring, this data is usually stored electronically in NMEA 0183 format and can be used in electronic navigation , for example to control an autopilot or to calculate the arrival time and fuel consumption.