I’m having an issue with trying to transform the coordinates of a point shapefile plotted in Madrid 1870 geographic coordinate system (WKID: 4903) to European Datum 1950 (WKID: 4230). When I put the shapefile into the project tool and select ED50 as the output coordinate system, it does not give me any options to transform the coordinate system, which it should. According to the EPSG Geodetic Parameter Registry there should be two valid transformations, plus one retired one (see attached). The point that I plotted in Madrid 1870 plots within the defined area of use according to EPSG.
I’ve tried creating a custom transformation using the parameters found in the EPSG registry (attached), but the transformation method (polynomial) does not appear in the list of options so I’m guessing this may be the issue.