ncreasing
             longitude is positive east: from the +X axis toward the +Y axis.

             [1,n] = size(lon); double = class(lon)

             The earth, moon, and sun are exceptions:
             planetographic longitude is measured positive east for
             these bodies.

             The default interpretation of longitude by this
             and the other planetographic coordinate conversion
             routines can be overridden; see the discussion in
             Particulars below f