GMT is a collection of tools that allow users to manipulate
 (x,y) and (x,y,z) data sets (including filtering, trend fitting, gridding,
 projecting, etc.) and produce Encapsulated PostScript File (EPS) illustrations
 ranging from simple x-y plots through contour maps to artificially illuminated
 surfaces and 3-D perspective views in black and white, gray tone, hachure
 patterns, and 24-bit color.
 .
 GMT supports many common map projections plus linear, log, and power scaling,
 and comes with support data such as coastlines, rivers, and political
 boundaries.