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Accurac
Section 1 Method 2 Remarks Equipment
y
Requires distance
Miscellaneous measurument. Best
4.7*** levelling Medium estimates for small Various
to high
devices gradients, especially
with best levels.
*Simple **more difficult ***most difficult.
The figure below shows two points A and B and a theodolite or
total station T set up on a tripod above a ground point G. Point A is
higher than the instrument and is above the horizontal plane through
T, whereas B is lower and below the horizontal plane. At T, the
instrument is mounted a vertical distance h above G on its tripod.
Figure 10.4. Angles measurement
The horizontal angle at T between A and B is not the angle in the
sloping plane containing A, T and B, but the angle θ on the horizontal
plane through T between the vertical planes containing the lines of
sight TA and TB.
The vertical angles to A and B from T are αA (an angle of
elevation) and αB (angle of depression) .
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