NAME

       MAPGCI - Returns a set of points on the shortest great circle route between two user-specified points on
       the globe.

SYNOPSIS

       CALL MAPGCI(ALAT,ALON,BLAT,BLON,NOPI,RLTI,RLNI)

C-BINDING SYNOPSIS

       #include <ncarg/ncargC.h>

       void c_mapgci( float alat, float alon, float blat,
       float blon, int nopi, float *rlti, float *rlni)

DESCRIPTION

       ALAT and ALON
                   (input  expressions,  of  type  REAL)  are  the  latitude  and  longitude of the point at the
                   beginning of a great circle route.

       BLAT and BLON
                   (input expressions, of type REAL) are the latitude and longitude of the point at the end of a
                   great circle route.

       NOPI        (an input expression, of  type  INTEGER)  is  the  number  of  equally-spaced  points  to  be
                   interpolated along the great circle route.

       RLTI and RLNI
                   (output  arrays  of  type  REAL,  each  dimensioned  at least NOPI) are arrays containing the
                   latitudes and longitudes of points interpolated along the great circle route.   Each  lat/lon
                   pair  defines  one of the points; they appear in order of increasing distance along the great
                   circle route.  The positions of the first point and the last point are not returned in  these
                   arrays; only the interpolated points are.

C-BINDING DESCRIPTION

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

USAGE

       The statement:

            CALL MAPGCI (ALAT,ALON,BLAT,BLON,NOPI,RLTI,RLNI)

       defines the positions of two points, A and B, on the globe and the number of equally-spaced points, NOPI,
       to  be  interpolated  along  the  great  circle  route  from A to B.  The latitudes and longitudes of the
       interpolated points are returned to the caller in the arrays RLTI and RLNI.  If the points A  and  B  are
       exactly  opposite one another on the globe, the code does not fail, but the direction of the great circle
       route will be somewhat unpredictable (since, in that case, there is more  than  one  great  circle  route
       joining the two points).

EXAMPLES

       Use the ncargex command to see the following relevant example: cmpgci.

ACCESS

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

SEE ALSO

       Online: ezmap, ezmap_params, mapaci, mapbla, mapblm, mapdrw,  mapeod,  mapfst,  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,  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

COPYRIGHT

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

UNIX                                               March 1993                                     MAPGCI(3NCARG)