||I need to transform data on Tanzania which is based on the Arc 1960 datum, but the Clarke 1880 Modified spheroid to WGS 84. GCS_ARc_1960 under the projection Utility, specifies Clarke 1880 RGS as the spheroid which is NOT what I want. The parameters of Clarke 1880 Arc are very similar to those of Clarke 1880 Modified (which is not listed). But I still need to select a datum that is placed in the correct position. Could anyone share some insight on which datum is where, which one is more suitable, or what is the current Tanzanian datum, that would be great.