This is Unit 3, Section 1 of Restoration of Lost Corners by Proportionate Measurement. A training program developed by the Branch of Cadastral Survey development of the Bureau of Land Management. In this part of Unit 3, we should learn the techniques for both two-point and one-point control of lost corners and how to apply them in possible field situations.

The first method of corner restoration which will be consider is two-point control. The following section describes what it is, where it is used, and how it is computed.

According to the manual, Section 5-29 defines the technique of two-point control where the intersecting lines have been established in only two directions. The record distances to the nearest identified corners on these two lines will control the position of temporary points. Then from those temporary points, cardinal offsets will be made to fix the corner point.

A common place where lines intersect with control, in only two directions, is at the intersection of township and range lines. An example of this would be the southeast corner of Township 5 North, Range 4 East.