Gmt

Generic Mapping Tools - data processing and display software package

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 24bit 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.

This port installs only the GMT manpages, there is a tutorial and documentation in .ps, .pdf and .html format on the ftp site, too.

In case you look for data to plot, there is topological data at ftp//topex.ucsd.edu/pub/global_topo_2min/topo_8.2.img 140MB, covers nearly the whole earth