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.

this package provides an interface for gnu octave to query and read/write gmt grid files.