This script takes an ASCII data file and writes a PostScript plot. Pdf and eps can be written if you have ghostscript installed. It also has an interactive mode. Tridens was formerly called hexdens. Tridens seems more logical. But there are very few things called hexdens, while there are hundred different things called tridens. Tridens also plots data on a rectangular grid.
Here is the program tridens , and the instructions . Type "tridens" at the command line to get started.
Pdf format examples: Here is a triangular example , and another , and a square example .