As I understand the original problem. it was to triangulate to locate one
of the NV beacons and the software I mention contains menu selection that
will do the needed calculation.


I don't dislike using the geodetic software to determine the intersection
point but as I said before I personally would work with UTM coordinates and
a simple law-of-sines calculation. The law-of-sines calculation could be
demonstrated in a small paragraph while the ellipsoidal intersection
calculation would be a page of formulas.

The final result of working with UTM is UTM and can always be converted to
latitude and longitude.

Also, with rectangular coordinates the problem could be worked out on graph
paper...or as I said before worked out graphically.

But suppose the compass readings were perfect and the distances involved
were 40 miles...and say that the becon is the size of a 16d nail and that
determination of its location is critcial within two diameters of the becon.
Is the compass pointing a rumb line or is the compass indicating an initial
direction ? In other words with the geodetic software are we seeking the
intersection of two great-circles or the intersection of two rumb lines ?


I would argue that rectangular coodrinates are used simply because we like
to think in straight lines, they are easy to construct, and on a small
scale they approximate a geodesic (great circle) on a sphere.

We do more than think in straight lines. Survey instruments run straight
lines or determine straight baselines. A control survey is points connected
with lines even though points on some curve near the control survey can be
set from the control survey...

The historical requirement of the division of Federal lands calls for the
construction of an East great-circle as points offset from a straight
baseline...In other words the straight baseline is the given and the
great-circle is the construction.