OpenOSX: GrassPro: GMT Surfaces

grdcontour	Contouring of 2-D .grd files: grdcontour reads a 2-D gridded file and produces a contour map by tracing each contour through the grid. As an option, the x/y/z positions of the contour lines may be dumped to a single multisegment file or many separate files, in addition the command creates a postscript plot which may be opened with Preview (which it will convert to a PDF file).
pscontour	Generates contour image or image raw table data by triangulation pscontour reads an ASCII [or binary] xyz-file and produces a raw contour plot by triangulation. By default, the optimal Delaunay triangulation is performed (using Shewchuk's method), but the user may provide an optional second file with network information, such as a triangular mesh used for finite element modeling. In addition to contour lines, the area between the contours may be filled according to a color palette file.
grdview	Produces a shaded or wireframe 3-D perspective image from a 2-D .grd file output to a new raster file. Optionally data sets may be draped on top of a surface, contours plotted on top of the surface, and apply artificial illumination based on intensities from a separate .grd file.
grdvolume	Calculates volume under a surface within a specified contour; the volume contained between the surface and the plane specified by the given contour
triangulate	Perform optimal Delauney triangulation and gridding to xyz data which will find the most ideal equilateral triangulation possible.
surface	A continuous curvature gridding algorithm with adjustable tension with lots of options.
grdimage	Produce images from 2-D gridded data sets, it reads one 2-D gridded file and produces a gray-shaded (or colored) map by assigning each z-value a gray-shade (or color).