Topcon AT-B2 - OPERATIONAL PROCEDURES; MEASURING HEIGHT DIFFERENCES

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6. OPERATION
1 Set up the instrument at a point approximately
halfway between points A and B. The reticle stadia
lines can be used to optically compare the
distances. (See "6.3 MEASURING DISTANCE
USING THE STADIA LINES".)
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• For more accurate measurement, set the instrument
as close to halfway as possible, to eliminate errors
due to sighting axis misalignment.
2 Position the staff vertically at point A.
Take the reading a (backsight) on the staff at point
A.
3 Then sight the staff at point B and obtain the
reading b (foresight).
4 The difference a - b is the height difference h of B
from A.
Example:
h = a - b = 1.735m - 1.224m = 0.511m
6.1 MEASURING HEIGHT DIFFERENCE