TRIANGULATE

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#ifdef SI #define UNIT cm #define LEN 15 #define SCALE -JM1 #else #define UNIT inch #define LEN 6 #define SCALE -JM6 #endif  

NAME

triangulate - Perform optimal Delauney triangulation and gridding  

SYNOPSIS

triangulate infiles [ -Ggrdfile ] [ -H ] [ -Ix_inc[m|c][/y_inc[m|c]] ] [ -Jparameters ] [ -M[flag] ] [ -Rwest/east/south/north ] [ -V ] [ -Z ] [ -: ] [ -b[i|o][d] ]  

DESCRIPTION

triangulate reads one or more ASCII [or binary] files (or standard input) containing x,y[,z] and performs Delauney triangulation, i.e., it find how the points should be connected to give the most equilateral triangulation possible. If a map projection is chosen then it is applied before the triangulation is calculated. By default, the output is triplets of point id numbers that make up each triangle. The id numbers refer to the points position in the input file. As an option, you may choose to create a multiple segment file that can be piped through psxy to draw the triangulation network. If G -I are set a grid will be calculated based on the surface defined by the planar triangles.
infiles
Data files with the point coordinates in ascii (or binary; see -b). If no files are given the standard input is read.
 

OPTIONS

#include "explain_-H.txt" -I x_inc [and optionally y_inc] sets the grid size for optional grid output (see -G). Append m to indicate minutes or c to indicate seconds. #include "explain_-j.txt"
-M
Output triangulation network as multiple line segments separated by a record whose first character is flag [>]. To plot, use psxy with the -M option (see Examples). #include "explain_-R.txt" #include "explain_-V.txt"
-Z
Controls whether binary data file has two or three columns [2]. Ignored if -b is not set. #include "explain_-t.txt"
-b
Selects binary input and output mode. Append i or o to select binary input or output only. [Default is ASCII]. Node ids are stored as binary 4-byte integer triplets. Append d to indicate double precision for binary data (if both binary input and output are selected they will have the same precision). -bo is ignored if -M is selected.
 

EXAMPLES

To triangulate the points in the file samples.xyz, store the triangle information in a binary file, and make a grid for the given area and spacing, try

triangulate samples.xyz -bo -R0/30/0/30 -I2 -Gsurf.grd > samples.ijk

To draw the optimal Delauney triangulation network based on the same file using a LEN-UNIT-wide Mercator map, try

triangulate samples.xyz -M -R-100/-90/30/34 SCALE | psxy -M -R-100/-90/30/34 SCALE -W2 -B1 > network.ps  

SEE ALSO

gmt, pscontour #include "refs.i" Watson, D. F., 1982, Acord: Automatic contouring of raw data, Comp. & Geosci., 8, 97-101.


 

Index

NAME
SYNOPSIS
DESCRIPTION
OPTIONS
EXAMPLES
SEE ALSO

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