orial radius
             `re' and a polar radius `rp'. Units of `re' must match those of
             `alt'.

             [1,1] = size(re); double = class(re)

      f      the flattening coefficient

             [1,1] = size(f); double = class(f)

                f = (re-rp) / re

             where rp is the polar radius of the spheroid. (More importantly
             rp = re*(1-f).) The units of `rp' match those of `re'.

   the call:

      jacobi = <b>cspice_drdpgr</b>( body, lon, lat, alt, re, f)

