Survey resection calculator

You need to know the positions of three observed points and the angles between them. Coordinates are WGS84 lat, long and calculations use Colorado State Plane North (NAD83).

P1 (left): mils
P2 (right): mils
The answer is:

All points must be selected so that angles P1, P2, P-Left-Center, and P-Right-Center are at least 400 milliradians, and preferably 533 milliradians. We also need to check that station P is not on or near a circle passing through Stations A, B, and C. The sum of all angles from P between Left-P-Center and Center-P-Right, and from Center between Left-Center-Right must not be between 2,845 mils and 3,555 mils.