MAPTRN(3NCARG)

💫 MAPTRN — it's giving "project points" ✨

okay bestie, welcome to MAPTRN from the NCAR GRAPHICS manual, section 3NCARG. this is the little routine that takes a spot on the globe and tells you where it lands in the u/v plane. lowkey iconic.

also!! heads up: SUPCON is an alternate name for the routine MAPTRN. same routine, two names, main character energy fr fr. 🫶

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✨ SYNOPSIS ✨

CALL MAPTRN (RLAT, RLON, UVAL, VVAL)

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🎀 C-BINDING SYNOPSIS 🎀

#include <ncarg/ncargC.h>

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

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💖 DESCRIPTION 💖

so here's the tea on the arguments:

• RLAT and RLON — these are input expressions, type REAL, and they're 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. no vibes-based out-of-range values, bestie, the range is the range. 😤
• UVAL and VVAL — these are output variables, type REAL, and together they define the point (UVAL,VVAL) which is the projection of (RLAT,RLON) in the u/v plane. the units of UVAL and VVAL depend on the projection, so don't come for them expecting one universal unit. 💅

and now the important bit, listen up: if the point is not projectable, UVAL is returned equal to 1.E12. if the point is projectable but sits outside the boundary of the map (as defined by the last call to MAPSET and by the value of the parameter 'EL'), then MAPTRN — unlike MAPTRA — still returns its u and v coordinates. yes, really. she's generous like that. ✨

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🌸 C-BINDING DESCRIPTION 🌸

the C-binding argument descriptions are the same as the FORTRAN argument descriptions. that's it, that's the section. copy-paste but make it C. 😌

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🔥 EXAMPLES 🔥

use the ncargex command to see the following relevant examples: cpex03, mpex09, bnchmk.

go look at them, they ate. 💅

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👑 ACCESS 👑

to use MAPTRN or c_maptrn, load the NCAR Graphics libraries ncarg, ncarg_gks, and ncarg_c — preferably in that order. order matters, don't be chaotic about it. 🧚

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💀 MESSAGES 💀

see the ezmap man page for a description of all EZMAP error messages and/or informational messages. if something's yelling at you, that's where the answers live. 🙈

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🌈 SEE ALSO 🌈

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, maptra, maptri, 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

(that list is long and she knows it. bookmark it, iykyk. 💜)

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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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okay and that's the whole page!! this was MAPTRN(3NCARG) from the NCAR GRAPHICS manual, and the footer said UNIX, March 1993. periodt. go project some points, bestie. 🦋💖✨