NADCON Datum Conversion Utility NADCON transforms latitude and longitude coordinate values between two geodetic coordinate systems known as “datums.” To do so, NADCON uses a pair of conversion grids that essentially provide a transformation “bridge” between the two datums. NADCON can transform between any two datums for which grids are available. (refer to “Available Datum Shifts” in the Help documentation).
To perform the conversions, the NADCON application reads input coordinate data and uses an algorithm developed by Warren T. Dewhurst, Ph.D., and described in NOAA Technical Memorandum NOS NGS-50, dated January, 1990, to calculate new coordinate values and shift offsets. Results are displayed in seconds and meters and the new values are written and displayed. Each conversion requires the presence of conversion grids that are pairs of binary files (*.las, *.los) made up of a grid array of datum shift values plus spatial location and parameter information. Datum shifts for each input value are calculated based on an algorithm that interpolates the positional data using a minimum curvature function. The new NADCON reproduces the conversions exactly the same as the prior version of NADCON.
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