Geotools currently try to select Bursa-Wolf parameters from the EPSG database using the following algorithm:
However this algorithm lead to the selection of the following parameters for EPSG:4312 ("MGI"):
This seem to be the values for Slovenia. The expected values should be:
This is in EPSG 6.12, Coordinate Transformation 1618: MGI to WGS 84 (3). The same issue apply to all projected CRS derived from the 4312 geographic CRS, like EPSG:31286
We need to improve the way Geotools selects the set of Bursa-Wolf parameters. Just looking at the source and target datum is not suffisient.
We also need a mechanism that warn the user when more than one set of Bursa-Wolf parameters were found for a given geographic CRS, so the user know that the set selected by Geotools may not be the most appropriate one. We also need a mechanism for forcing the selection of a particular set of Bursa-Wolf parameters, to override the automatic selection.