If is the longitude and is the latitude, the coordinate transformations are similar to if you were using spherical polar coordinate convention.

The difference between geographic convention (G) and spherical polar convention (SP) is in the definition of . In G, this angle takes on the value 0 at the equator, 90 at the north pole and -90 at the south pole. In SP theta has 0 at the north pole and increases to 180 at the south pole. The difference in the transformations is that and are switched between conventions.