Sokkia SRX1 Operator's Manual page 96

16. RESECTION MEASUREMENT

Precaution when performing resection
In some cases it is impossible to calculate the coordinates of an unknown point (instrument
station) if the unknown point and three or more known points are arranged on the edge of a
single circle.
An arrangement such as that shown below is desirable.
It is sometimes impossible to perform a correct calculation in a case such as the one below.
When they are on the edge of a single circle, take one of the following measures.
(1) Move the instrument station as close as possible
to the center of the triangle.
(2) Observe one more known point which is not on the
circle.
(3) Perform a distance measurement on at least one
of the three points.

• In some cases it is impossible to calculate the coordinates of the instrument station if the included
angle between the known points is too small. It is difficult to imagine that the longer the distance
between the instrument station and the known points, the narrower the included angle between the
known points. Be careful because the points can easily be aligned on the edge of a single circle.
88
: Unknown point
: Known point