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14. 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.
: Unknown point
: Known point