GMT is an open source collection of about 90 command-line tools for manipulating geographic and Cartesian data sets (including filtering, trend fitting, gridding, projecting, etc.) and producing PostScript illustrations ranging from simple x–y plots via contour maps to artificially illuminated surfaces and 3D perspective views. The GMT supplements add another 50 more specialized and discipline-specific tools. GMT supports over 30 map projections and transformations and requires support data such as GSHHG coastlines, rivers, and political boundaries and optionally DCW country polygons.

GMT is developed and maintained by the GMT Team, with help from a global set of contributors and support by the National Science Foundation. It is released under the GNU Lesser General Public License version 3 or any later version.

Considering its flexibility at no charge, people worldwide are using GMT in their work and at home. Most users of GMT are Earth, ocean or planetary scientists, but there are apparently no limits to the kind of applications that may benefit from GMT. We know GMT is used in medical research, engineering, physics, mathematics, social and biological sciences, and by geographers, fisheries institutes, oil companies, a wide range of government agencies, and last but not least innumerable hobbyists.

If you think it is appropriate, you may consider paying us back by including our latest article in the reference list of your future publications that will benefit from the availability of GMT:

Wessel, P., Luis, J., Uieda, L., Scharroo, R., Wobbe, F., Smith, W. H. F., & Tian, D. (2019). The Generic Mapping Tools Version 6. Geochemistry, Geophysics, Geosystems, 20. https://doi.org/10.1029/2019GC008515

GMT has been installed successfully under UNIX/Linux/OS X on workstations. It also installs under Windows and in UNIX emulators such as Cygwin or on virtual machines. We anticipate few problems if you are installing the package on other platforms.

Note there are three GMT tar archives available (#3 is optional):

1. gmt-6.x.x.tar.bz2: The GMT 6 distribution
2. gshhg-gmt-2.x.x.tar.gz: All five resolutions of GSHHG coastline data
3. dcw-gmt-1.x.x.tar.bz2: Digital Chart of the World polygon data

For macOS and Windows users there are separate installers available. You can obtain GMT and support data from the GMT main site.

Refer to the install instructions to install GMT, and build instructions to build GMT from the sources.

GMT users elsewhere have developed programs that utilize the GMT libraries and produce PostScript code compatible with the rest of GMT or simply perform data manipulation. Currently, the supplemental archive include these directories:

• geodesy: Velocity arrows and error ellipses, solid Earth tides, GPS gridding.
• gshhg: Data extractor for GSHHG shoreline polygons and rivers, borders.
• img: Data extractor for Smith/Sandwell altimetry grids.
• mgd77: Programs for handling of native MGD77 files.
• potential: Geopotential manipulations.
• segy: Plotting SEGY seismic data sets.
• seis: Plotting of focal mechanisms and SAC (seismic Analysis Code) data.
• spotter: Plate tectonic & kinematics applications.
• x2sys: Track intersection (crossover) tools.

Before running programs, there are a few things you should do/know:

Read carefully the documentation for the gmt system. This can be
found as HTML files in the doc/html directories.
The successful operation of gmt-programs depends directly on your
understanding of how gmt "works", its option lists, I/O, and composite
plot mechanisms. Then, before running individual gmt programs, read
the associated man page.

You haven't bought anything so you cannot expect full service. However, if you find a bug in any of the programs, please report it to us by opening a issue rather than trying to fix it yourself so that we, and through us, other users may benefit from your find. Make sure you provide us with enough information so that we can recreate the problem.

For general questions, please post on the GMT Community Forum.