Co-ordinates

Co-ordinates are a set of numbers that define a position on the earth’s surface. In aviation, the most common coordinate system is geographic coordinates — latitude and longitude — expressed in degrees, minutes, and seconds (or decimal degrees). Waypoints, reporting points, and airspace boundaries are all defined by geographic coordinates.

Latitude and Longitude

• Latitude: The angular distance north or south of the equator; ranges from 0° (equator) to 90°N or 90°S (poles)
• Longitude: The angular distance east or west of the Prime Meridian (Greenwich); ranges from 0° to 180°E or 180°W

Precision in Aviation

Navigation databases, GPS receivers, and ATC systems use coordinates to define positions precisely. One degree of latitude equals approximately 60 NM. One minute of latitude equals 1 NM — the basis of the nautical mile definition. One degree of longitude varies from approximately 60 NM at the equator to zero at the poles.

Related Terms

See also: RNAV, Waypoint (RNAV), GPS.