HP,
Kind of the same principle:
1. Military Triangulation is when you use (at least) three spotters/RDF's (Radio Direction Finders)/terrain features. It all depends on what you want to triangulate.
a. If you are looking for an enemy Communication Center, you deploy at least three RDF's in different directions. When the enemy keys the mic on their radio, each RDF Operator calls in their position and the direct true degree coordinate to the enemy transmission. HQ plots each RDF Position on a map, they then draw a line in the direction indicated. The spot where the three lines intersect is where the enemy antenna is. They call that GPS/Grid Coord to FA (Field Artillery) who then pounds the area with HE Rounds. That is what we USED to do. Nowadays, Artillery have radar and computers that spot an incoming artillery round as it leaves the barrel of an enemy artillery piece, performs necessary calculations and fires a counterbattery round. Our rounds hit the enemy artillery before they reach the top of their arc.
b. Spotters are the same principle as RDF's, except they see the enemy, find the degree line to the enemy. HQ finds the intersection and calls in an Air or Artillery Strike.
c. Terrain Features are used in Land Navigation. They can be used in many ways, but to use them for triangulation, you just pick out three or more very large landmarks (mountains, rivers, creeks, roads, etc). Use a compass/sun/Polaris to find the degree heading each feature is from you. Using that number, shoot a back azimuth to find your direction from each feature. Find each feature on your TOPO Map, and mark your direction from each feature. Draw a line in that direction on your TOPO. Where the lines intersect......there you are!
d. Spanish Treasure! Usually a burial hidden in triangulation is marked as a dot in the middle of a triangle. If you see that, then you have to find the three corner markers. Usually, the North marker is what is called a "compass marker". Typically a large flat rock that is supported by three basketball sized rocks. You can always see light underneath. From there you have to figure what other corner markers were used. When you find all three markers, you measure the distance between each two markers to find the exact middle of each arm of the triangle. Draw a straight line from each corner to the center of the opposite arm. The spot to dig is where the three lines intersect.
While its not rocket science, it is basic Geometry. Don't always think its going to be an Equilateral Triangle (equal sides). It could be a triangle of any shape (Isosceles, Acute, Right, Scalene, or Obtuse).
Mike