1MAPGCI(3NCARG)                   NCAR GRAPHICS                  MAPGCI(3NCARG)
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NAME

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

10       CALL MAPGCI(ALAT,ALON,BLAT,BLON,NOPI,RLTI,RLNI)
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C-BINDING SYNOPSIS

13       #include <ncarg/ncargC.h>
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15       void c_mapgci( float alat, float alon, float blat,
16       float blon, int nopi, float *rlti, float *rlni)
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DESCRIPTION

19       ALAT and ALON
20                   (input expressions, of type REAL) are the latitude and
21                   longitude of the point at the beginning of a great circle
22                   route.
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24       BLAT and BLON
25                   (input expressions, of type REAL) are the latitude and
26                   longitude of the point at the end of a great circle route.
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28       NOPI        (an input expression, of type INTEGER) is the number of
29                   equally-spaced points to be interpolated along the great
30                   circle route.
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32       RLTI and RLNI
33                   (output arrays of type REAL, each dimensioned at least
34                   NOPI) are arrays containing the latitudes and longitudes of
35                   points interpolated along the great circle route.  Each
36                   lat/lon pair defines one of the points; they appear in
37                   order of increasing distance along the great circle route.
38                   The positions of the first point and the last point are not
39                   returned in these arrays; only the interpolated points are.
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C-BINDING DESCRIPTION

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

46       The statement:
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48            CALL MAPGCI (ALAT,ALON,BLAT,BLON,NOPI,RLTI,RLNI)
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50       defines the positions of two points, A and B, on the globe and the
51       number of equally-spaced points, NOPI, to be interpolated along the
52       great circle route from A to B.  The latitudes and longitudes of the
53       interpolated points are returned to the caller in the arrays RLTI and
54       RLNI.  If the points A and B are exactly opposite one another on the
55       globe, the code does not fail, but the direction of the great circle
56       route will be somewhat unpredictable (since, in that case, there is
57       more than one great circle route joining the two points).
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EXAMPLES

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

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

67       Online: ezmap, ezmap_params, mapaci, mapbla, mapblm, mapdrw, mapeod,
68       mapfst, mapgrd, mapgrm, mapgtc, mapgti, mapgtl, mapgtr, mapint, mapiq,
69       mapiqa, mapiqd, mapiqm, mapit, mapita, mapitd, mapitm, maplbl, maplmb,
70       maplot, mappos, maproj, maprs, maprst, mapsav, mapset, mapstc, mapsti,
71       mapstl, mapstr, maptra, maptri, maptrn, mapusr, mapvec, mpchln, mpfnme,
72       mpgetc, mpgeti, mpgetl, mpgetr, mpglty, mpiaty, mpifnb, mpilnb, mpiola,
73       mpiosa, mpipai, mpipan, mpipar, mpisci, mplnam, mplndm, mplndr, mplnri,
74       mpname, mprset, mpsetc, mpseti, mpsetl, mpsetr, supmap, supcon,
75       ncarg_cbind
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77       Hardcopy: NCAR Graphics Contouring and Mapping Tutorial
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80       Copyright (C) 1987-2009
81       University Corporation for Atmospheric Research
82       The use of this Software is governed by a License Agreement.
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86UNIX                              March 1993                    MAPGCI(3NCARG)
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