Map Projections Described
In the following sections, the available IDL projections are discussed in detail. The projections are grouped within three categories: azimuthal, cylindrical, and pseudo-cylindrical.
The General Cartographic Transformation Package (GCTP) map projections are not described here. Documentation for the GCTP package is available from the US Geologic Survey at http://mapping.usgs.gov.
In this text, the plane of the projection is referred to as the UV plane with horizontal axis u and vertical axis v.