MAPTRA - Projects points.

       To  use MAPTRA or c_maptra, load the NCAR Graphics libraries ncarg, ncarg_gks, and ncarg_c, preferably in
       that order.

       The C-binding argument descriptions are the same as the FORTRAN argument descriptions.

       #include <ncarg/ncargC.h>

       void c_maptra (float rlat, float rlon, float *uval,
       float *vval)

       Copyright (C) 1987-2009
       University Corporation for Atmospheric Research
       The use of this Software is governed by a License Agreement.

UNIX                                               March 1993                                     MAPTRA(3NCARG)

       RLAT and RLON
                   (input expressions, of type REAL) are the latitude and longitude, respectively, of a point on
                   the  globe.  RLAT  must  be  between -90. and +90., inclusive; RLON must be between -540. and
                   +540., inclusive.

       UVAL and VVAL
                   (output variables, of type REAL) define the point (UVAL,VVAL) that is the projection  in  the
                   u/v plane of (RLAT,RLON). The units of UVAL and VVAL depend on the projection.

                   If  the  point  is not projectable or if it is outside the boundary of the map (as defined by
                   the last call to MAPSET and by the value of the parameter 'EL'), UVAL is  returned  equal  to
                   1.E12.

       Use the ncargex command to see the following relevant examples: ccpmpxy, cmptra, fgkgtx, fngngdts.

       MAPTRA - Projects points.

       Online: ezmap, ezmap_params, mapaci, mapbla, mapblm, mapdrw,  mapeod,  mapfst,  mapgci,  mapgrd,  mapgrm,
       mapgtc,  mapgti,  mapgtl,  mapgtr,  mapint, mapiq, mapiqa, mapiqd, mapiqm, mapit, mapita, mapitd, mapitm,
       maplbl, maplmb, maplot, mappos, maproj, maprs, maprst, mapsav, mapset, mapstc,  mapsti,  mapstl,  mapstr,
       maptri,  maptrn,  mapusr, mapvec, mpchln, mpfnme, mpgetc, mpgeti, mpgetl, mpgetr, mpglty, mpiaty, mpifnb,
       mpilnb, mpiola, mpiosa, mpipai, mpipan, mpipar, mpisci, mplnam, mplndm, mplndr, mplnri,  mpname,  mprset,
       mpsetc, mpseti, mpsetl, mpsetr, supmap, supcon, ncarg_cbind

       Hardcopy: NCAR Graphics Contouring and Mapping Tutorial

       CALL MAPTRA (RLAT,RLON,UVAL,VVAL)