triangulation point 
noun
Another term for trig point.After a couple of miles, we reached the high point of the walk, a triangulation point at 1,000 feet gleaming with fresh white paint....
- Follow the broad southern ridge to the summit triangulation point, and take care, for this is easily missed in poor visibility.
- He started with his house and local church towers as the triangulation points, eventually computing the distance between Alkmaar in the North and Bergen-op-Zoom in the South, a distance of 130 km.