| Summary: | Surveying with GPS produces ellipsoid height, however for the practical purposes, orthometic height is used rather than ellipsoid height. Meanwhile leveling height is closer to orthometric height sistem. Ellipsoid height can be reduced to orthometric height if geoid undulation is known. Geoid undulation data can be obtained from a geoid model. In Indonesia, the working to calculate the geoid model is still in progress. Due to above, this research assumes the geoid as a pure geometric plane, so that a simple geomatric model such"as transformation conform can be applied to connect the geoid and ellipsoid reference.
This research changes GPS height become close to leveling height by transformation technique. Transformation was done at two locations with difference on terrain conditions. At both locations, leveling height and GPS height were available.
Result from this investigation shows that the average difference between leveling height and height obtained from transfor
mation is 3cm. Meanwhile, the leveling height difference (AHLEv) deviates from the associated transformed difference (A1-1
-TRANS)
with the average value is 1.85ppm ( < 7mmVD).
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