Web-based Datum Transformation Tool

The Web-based Transformation Tool provides instant conversion between HK 1980 Grid Coordinates, HK 1980 Geodetic Coordinates, WGS84 Latitude and Longitude (ITRF96), UTM Grid Coordinate or UTM Grid Reference (ITRF96). The Transformation Tool uses the conversion methods, parameters and formulas listed in the "Explanatory Notes on Geodetic Datums in Hong Kong" (PDF) and the "Datum Transformation and Transformation Parameters" (The "7-parameters") (PDF). It can convert up to 10 point coordinates at one time. It is only applicable for coordinates within Hong Kong.

Note: Users SHOULD NOT use coordinates derived from datum transformation for applications requiring precise point positions. Transformation between datums does not improve the accuracy. In most cases, the transformation coordinates would be less accurate because of the errors in the transformation and projection computation would be added to the results. Please seek advice from professional land surveyors.