The equidistant conic projection was described by the Greek philosopher
Claudius Ptolemy about A.D. 150. It is neither conformal or equal-area, but
serves as a compromise between them. The scale is true along all meridians and
the standard parallels.
The projection is set with d or D. The projection center is set by
lon0/lat0 and two standard parallels for the map are set with lat1/lat2.
The figure size is set with scale or width.