Here are the Matlab files you need. Put them in the same directory
and run the tri script. It calls the rest.
tri.m--Does most of the work--partially modified
from the triplot.m function of Middleton.
pitch.m--Simple determination of pitch (rake)
given plunge and dip--this is now not necessary and the functionality is incorporated into tri.m
pt.m--Plots a point on the diagram given the dip
and the pitch. This one uses simple trig. It could have been
much fancier and intersected the pitch and dip lines.