Geodetic Datum Transformations

This presentation covers issues relating to datum transformations between the several horizontal/geometric and vertical geodetic datums most commonly used in the United States. The presentation demonstrates and examines several commonly used transformation utilities from NGS and the National Geospatial-Intelligence Agency (NGA) specifically, the NGS Coordinate Conversion and Transformation tool (NCAT),  VDatum Transformations, 3-parameter abridged Molodensky transformations originally computed by the U.S. Defense Mapping Agency (DMA) and the more rigorous 14-parameter Helmert transformations supported by the NGS HTDP (Horizontal Time Dependent Positioning) utility.