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Man Pages

Manual Reference Pages  -  GMT (1)


GMT - The Generic Mapping Tools data processing and display software package


Gmt Overview


GMT is a collection of public-domain Unix tools that allows you to manipulate x,y and x,y,z data sets (filtering, trend fitting, gridding, projecting, etc.) and produce PostScript illustrations ranging from simple x-y plots, via contour maps, to artificially illuminated surfaces and 3-D perspective views in black/white or full color. Linear, log10, and power scaling is supported in addition to 25 common map projections. The processing and display routines within GMT are completely general and will handle any (x,y) or (x,y,z) data as input.


GMT is also a wrapper script that can start any of the programs:

GMT module module-options

where module is the name of a GMT program and the options are those that pertain to that particular program.


The following is a summary of all the programs supplied with GMT and a very short description of their purpose. Detailed information about each program can be found in the separate manual pages.

blockmean               L2 (x,y,z) data filter/decimator
blockmedian     L1 (x,y,z) data filter/decimator
blockmode               Mode (x,y,z) data filter/decimator
filter1d                Filter 1-D data sets (time series)
fitcircle               Finds the best-fitting great circle to a set of points
gmt2rgb         Convert Sun rasterfile or grid to r, g, b grids
gmtconvert      Convert between ASCII and binary 1-D tables
gmtdefaults     List the current default settings
gmtmath         Mathematical operations on data tables
gmtset          Set individual default parameters
gmtselect               Extract data subsets based on spatial criteria
grdfilter               Filter 2-D data sets in the space domain
grd2cpt         Make a color palette table from grid files
grd2xyz         Conversion from 2-D grid file to table data
grdblend                Blend several partially over-lapping grid files onto one grid
grdclip         Limit the z-range in gridded data
grdcontour      Contouring of 2-D gridded data
grdcut          Cut a sub-region from a grid file
grdedit         Modify header information in a 2-D grid file
grdfft          Operate on grid files in the wavenumber (or frequency) domain
grdgradient     Compute directional gradient from grid files
grdhisteq               Histogram equalization for grid files
grdimage                Produce images from 2-D gridded data
grdinfo         Get information about grid files
grdlandmask     Create mask grid file from shoreline data base
grdmask         Reset nodes outside a clip path to a constant
grdmath         Mathematical operations on grid files
grdpaste                Paste together grid files along a common edge
grdproject      Project gridded data onto a new coordinate system
grdreformat     Converting between different grid file formats
grdsample               Resample a 2-D gridded data set onto a new grid
grdtrend                Fits polynomial trends to grid files
grdtrack                Sampling of 2-D data set along 1-D track
grdvector               Plot vector fields from grid files
grdview         3-D perspective imaging of 2-D gridded data
grdvolume               Volume calculations from 2-D gridded data
greenspline     Interpolation using Green’s functions for splines in 1-3 dimensions
makecpt         Make color palette tables
mapproject      Forward or inverse map projections of table data
minmax          Find extreme values in data tables
nearneighbor    Nearest-neighbor gridding scheme
project         Project data onto lines/great circles
ps2raster               Crop and convert PostScript files to raster images, EPS, and PDF
psbasemap               Create a basemap plot
psclip          Use polygon files to define clipping paths
pscoast         Plot coastlines and filled continents on maps
pscontour               Contour xyz-data by triangulation
pshistogram     Plot a histogram
psimage         Plot images (EPS or Sun raster files) on maps
pslegend                Plot legend on maps
psmask          Create overlay to mask out regions on maps
psrose          Plot sector or rose diagrams
psscale         Plot gray scale or color scale on maps
pstext          Plot text strings on maps
pswiggle                Draw time-series along track on maps
psxy                    Plot symbols, polygons, and lines on maps
psxyz           Plot symbols, polygons, and lines in 3-D
sample1d                Resampling of 1-D table data sets
spectrum1d      Compute various spectral estimates from time-series
splitxyz                Split xyz-files into several segments
surface         A continuous curvature gridding algorithm
trend1d         Fits polynomial or Fourier trends to y = f(x) data
trend2d         Fits polynomial trends to z = f(x,y) data
triangulate     Perform optimal Delaunay triangulation and gridding
xyz2grd         Convert equidistant xyz data to a 2-D grid file


Look up the individual man pages for more details and full syntax. Run GMT without options to list all GMT programs and to show all installation directories. Information is also available on the GMT home page


Wessel, P., and W. H. F. Smith, 2015, The Generic Mapping Tools (GMT) version 4.5.14 Technical Reference & Cookbook, SOEST/NOAA.
Wessel, P., and W. H. F. Smith, 1998, New, Improved Version of Generic Mapping Tools Released, EOS Trans., AGU, 79 (47), p. 579.
Wessel, P., and W. H. F. Smith, 1995, New Version of the Generic Mapping Tools Released, EOS Trans., AGU, 76 (33), p. 329.
Wessel, P., and W. H. F. Smith, 1995, New Version of the Generic Mapping Tools Released,, Copyright 1995 by the American Geophysical Union.
Wessel, P., and W. H. F. Smith, 1991, Free Software Helps Map and Display Data, EOS Trans., AGU, 72 (41), p. 441.
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GMT 4.5.14 GMT (1) 1 Nov 2015

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