# GMT

NAME
INTRODUCTION
SYNOPSIS
GMT OVERVIEW
SEE ALSO
REFERENCES

## NAME

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

## INTRODUCTION

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.

## SYNOPSIS

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.

## GMT OVERVIEW

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 a grid file
|  | grd2xyz |  |  | Conversion from 2-D gridded 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 gridded 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
|  | makecpt |  |  | Make GMT 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

## SEE ALSO

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 gmt.soest.hawaii.edu

## REFERENCES

Wessel, P., and W. H. F. Smith, 2005, The Generic Mapping Tools (GMT) version 4.1 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, http://www.agu.org/eos_elec/95154e.html, 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.