Following examples are calculated with BestTachySpot.
You may have experienced this before. You are defining a new station and all points with known coordinates are more or less in the same direction. Be careful in this situation.
The situation explained with an example:
Resection on point 1 with observations to known backsight points on the road north of the site (green in following figure). Goal is to find the coordinates of point 5.
Accuracy (blue error ellipse in map):
Standard deviation is ver