when the instrument station is outside the circumscribing circle its location is always on the opposite side of the ray to the most distant point as the inter-section of the other two rays

If f_{1} and f_{2} are the distances from the optical centre of a convex lens of focal length f to conjugate two points P_{1} and P_{2} respectively, the following relationship holds good

If arithmetic sum of latitudes of a closed traverse is ∑Lat and closing error in latitude is dx, the correction for a side whose latitude is l, as given by Transit Rule, is