MAPGCI(3NCARG)

✨ MAPGCI ✨

okay bestie, welcome to the NCAR GRAPHICS corner of the manual — this one lives in section 3NCARG and it's literally the glow-up your globe needed 💅

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🌸 NAME 🌸

MAPGCI — gives you back a whole set of points sitting on the shortest great circle route between two points you picked on the globe. it's giving ✈️ but make it math.

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🎀 SYNOPSIS 🎀

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

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🦋 C-BINDING SYNOPSIS 🦋

#include <ncarg/ncargC.h>

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

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💖 DESCRIPTION 💖

• ALAT and ALON — (input expressions, type REAL) the latitude and longitude of the point where your great circle route starts. the origin story, if you will 🫶
• BLAT and BLON — (input expressions, type REAL) the latitude and longitude of the point where that great circle route ends. the destination era.
• NOPI — (an input expression, type INTEGER) how many equally-spaced points you want interpolated along the great circle route. you choose the count, queen 👑
• RLTI and RLNI — (output arrays of type REAL, each dimensioned at least NOPI) these are the arrays holding the latitudes and longitudes of the points interpolated along the great circle route. each lat/lon pair = one point, no cap. they show up in order of increasing distance along the great circle route. and listen — the positions of the first point and the last point are NOT returned in these arrays. only the interpolated ones. so don't come for me when A and B aren't in there 😭

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🌈 C-BINDING DESCRIPTION 🌈

the C-binding argument descriptions are literally the same as the FORTRAN argument descriptions. same facts, different font. periodt 💅

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⭐ USAGE ⭐

this statement right here:

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

defines the positions of two points, A and B, on the globe, plus the number of equally-spaced points, NOPI, to be interpolated along the great circle route from A to B. the latitudes and longitudes of those interpolated points get returned to the caller in the arrays RLTI and RLNI. simple, clean, iconic ✨

🚨 okay so important: 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. that's because in that case there is more than one great circle route joining the two points. so it's not a bug, it's just the universe being mysterious 🙈

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🔥 EXAMPLES 🔥

use the ncargex command to see the following relevant example: cmpgci. go look, it slays.

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💜 ACCESS 💜

to use MAPGCI or c_mapgci, load the NCAR Graphics libraries ncarg, ncarg_gks, and ncarg_c — preferably in that order. order matters, bestie, don't freestyle it 🎀

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👑 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 📚

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🍓 COPYRIGHT 🍓

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

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and that's the whole page, bestie 🫶 this was MAPGCI(3NCARG) from the UNIX manual, dated March 1993 — yeah she's vintage, she's an icon, she's been serving great circles since before we were born 💀✨