I have posted a law-of-cosines calculation example several times where
coordinates of an intersection point are determined from two GPS locations
with a bearing from each location...to the intersection point. I can find
one of those in my files and post it later if that is needed.


Oh, intersection of two directions is fundamentally a law-of-sines
calculation and that is a much easier calculation than a law-of-cosines
calculation. A law-of-cosines calculation is use for the intersection of two
distances...

But it could been done graphically with 'Scratch-Plot' because one of the
newer features of 'Scratch-Plot' is a plot by azimuth and distance. Just
set-up a scale of UTM coordinates, plot each GPS location in UTM
coordinates, plot a line from each location with an azimuth direction and
a dummy-distance so that the lines intersect, mouse-click a point at the
intersection of the lines, and check the coordinates of the mouse-click
point immediately in the help file or later in the plot text file.


Compass directions with declination should also be adjusted with UTM
convergence before they are used with UTM coordinates...