Leica GPS1200 Series Technical Reference Manual page 1258

Survey - Hidden Points
Step Description
When STORE (F1) is pressed in HIDDEN PT Hidden Point Meas-
urement, the height of the hidden point is computed and stored.
For hidden point measurement methods using two known points, this
is done for each known point. In this case, the height of the hidden
point is the average.
GPS1200 1258
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