Planetographic coordinate system Filter Planetographic coordinate system topics

Geographic coordinates are used on the surface of the Earth. An equivalent system called planetographic coordinates is used for other planets. Alternative titles, such as areographic coordinates on Mars, selenographic coordinates on the Moon, and heliographic coordinates on the Sun, are sometimes used to refer to the equivalent systems.

For each planet, a system of longitude lines is set up by first defining a prime meridian to act as the origin of longitude. The prime meridian is an arbitrarily chosen meridian, typically passing through a prominent feature of the planet, such as a crater.

The other component of planetographic coordinates is latitude. Latitude lines are circles centered on the axis of a planet. The zero of latitude is at the equator, and 90 degrees is at the north pole. The north pole is distinguished from the south by the fact that when viewed from above, the planet's rotation is counterclockwise.

In summary, planetographic coordinates are a system of coordinates created by the setting up of longitudinal and latitudinal lines on planets. A prime meridian is defined by the position of some prominent feature; positive longitude is in the direction of rotation, and positive latitude is in the direction of the north pole.