GMT is an open source collection of ~80 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 ~40 more specialized tools.
GMT supports over 30 map projections and transformations and comes with support
data such as GSHHG coastlines, rivers, and political boundaries.  GMT is
developed and maintained by Paul Wessel, Walter H. F. Smith, Remko Scharroo,
Joaquim Luis, and Florian Wobbe, with help from a global set of volunteers, and
is supported by the National Science Foundation.  It is released under the GNU
Lesser General Public License.
