CSSTRI(3NCARG)

💖 CSSTRI — it's giving Delaunay triangulation, but make it spherical 💖

okay so bestie, welcome to the NCAR GRAPHICS manual page for CSSTRI, living in section 3NCARG of your friendly neighbourhood Unix man pages. this one is a Fortran-callable routine and it is literally the girl who figures out a Delaunay triangulation for data scattered on a sphere. no cap. ✨

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🦋 NAME 🦋

CSSTRI — calculates a Delaunay triangulation for data on a sphere.

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🌸 SYNOPSIS 🌸

CALL CSSTRI (N, RLAT, RLON, NT, NTRI, IWK, RWK, IER)

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✨ DESCRIPTION ✨

here's the cast of characters, and every single one of them matters, okay? 🫶

• N — (integer, input) the number of input data points. and it must be N > 2, periodt. 💅
• RLAT — (real, input) an array holding the latitudes of the input data, in degrees. ⚠️ important: the first three points must not be collinear (meaning they can't all lie on a common great circle). do not test her on this one.
• RLON — (real, input) an array holding the longitudes of the input data, expressed in degrees.
• NT — (integer, output) the number of triangles in the triangulation — unless IER .NE. 0, in which case NT = 0. so let NB be the number of boundary points on the convex hull of the data: if NB .GE. 3, then NT = 2N-NB-2, otherwise NT=2N-4. the input data are considered to be bounded if they all lie in one hemisphere. and bestie, dimensioning NT for 2*N will always work. always. slay. 👑
• NTRI — (integer, output) a two-dimensional integer array dimensioned for 3 x NT, where NT is the number of triangles in the triangulation (NT is at most 2*N). NTRI contains the triangulation data. the vertices of the Kth triangle are:

(PLAT(NTRI((1,K)),PLON(NTRI(1,K)),
(PLAT(NTRI((2,K)),PLON(NTRI(2,K)),
(PLAT(NTRI((3,K)),PLON(NTRI(3,K))

• IWK — (integer, input) an integer workspace of length 27*N.
• RWK — (double precision, input) a work array dimensioned for 13*N. 🚨 note that this work array must be typed DOUBLE PRECISION. like, that's not a suggestion, that's the vibe check.
• IER — (integer, output) an error return value. if IER comes back as 0, then no errors were detected — iconic behaviour. if IER is non-zero, then go refer to the man page for cssgrid_errors for details. 🙈

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🎀 USAGE 🎀

CSSTRI is called to find a Delaunay triangulation of data randomly positioned on the surface of a sphere. 🌍✨

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🌈 ACCESS 🌈

to use CSSTRI, load the NCAR Graphics library ngmath. that's the whole assignment.

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💜 SEE ALSO 💜

• css_overview
• cssgrid
• csvoro

complete documentation for Cssgrid is available at URL

http://ngwww.ucar.edu/ngdoc/ng/ngmath/cssgrid/csshome.html

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👑 COPYRIGHT 👑

Copyright (C) 2000
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 one came from the UNIX manual, dated May 2000, filed under CSSTRI(3NCARG) — go forth and triangulate responsibly, mwah 💅🌸