Height survey
Some municipalities require height surveys to verify that the peak of the roof does not exceed a certain height. The height is based on the elevation difference between original ground, prior to excavation/construction, and the peak of the roof.
We gather ground elevations while performing the foundation staking and then check the elevation (compared to plans) of the foundation while preforming the foundation survey.
This allows the builder to make corrections, if necessary, while under construction rather than after the fact.