MAPGRD - Draws a lat/lon grid.

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

       #include <ncarg/ncargC.h>

       void c_mapgrd()

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

UNIX                                               March 1993                                     MAPGRD(3NCARG)

       MAPGRD has no arguments.

       Use the ncargex command to see the following relevant examples: ccpcica, ccpmovi, cmpclr, cmpdd, cmpgrd,
       cmplbl, cmplot, cmptit, epltch, ffex02, fpchiqu.

       MAPGRD - Draws a lat/lon grid.

       Online: ezmap, ezmap_params, mapaci, mapbla, mapblm, mapdrw, mapeod, mapfst, mapgci, 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, maptra,
       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 MAPGRD

       The statement:

            CALL MAPGRD

       draws a grid consisting of lines of constant latitude (parallels) and lines of constant longitude
       (meridians), spaced as specified by the value of the internal parameter 'GR'.  If EZMAP needs
       initialization or if the value of 'GR' is less than or equal to zero or if there is an uncleared NCAR
       Graphics error, MAPGRD does nothing.

       The grid is drawn using calls to MAPIT and MAPIQ.  By default, MAPGRD temporarily forces the value of the
       internal parameter 'DL' to zero, so that the grid will be drawn using calls to the routines FRSTD and
       VECTD, in the dash package.  MAPGRD also temporarily forces the use of the dash pattern defined by the
       internal parameter 'DA'.  A user version of the routine MAPUSR may be supplied to change the way in which
       grid lines are drawn.  Before returning control to the user, MAPGRD restores the original value of 'DL'
       and resets the current dash pattern to be used by the dash package.