Jan Jezek a écrit :
> After digging EPSG database I've found strange behavior of math transform 
> finding. When I have CRS where the transformation to WGS84 (4326) is defined 
> as concatenated operation then I'm able to transform to 4326 properly, but I 
> can't transform to other CRSs though they have definition for transformation 
> to the 4326 (for example from 4818 to 4324). Or in deed - I can but with 
> 'Bursa wolf parameters required' Exception. Isn’t that a bug?

Maybe it is not a matter of ConcatenatedTransform (but I'm not sure). I just 
tried the following:

java org.geotools.referencing.CRS -colors -authority=EPSG 4818 4324

and got:

GEOGCS["S-JTSK (Ferro)",
   DATUM["S-JTSK (Ferro)",
     SPHEROID["Bessel 1841", 6377397.155, 299.1528128, 
AUTHORITY["EPSG","7004"]],
     AUTHORITY["EPSG","6818"]],
   PRIMEM["Ferro", -17.666666666666668, AUTHORITY["EPSG","8909"]],
   UNIT["degree", 0.017453292519943295],
   AXIS["Geodetic latitude", NORTH],
   AXIS["Geodetic longitude", EAST],
   AUTHORITY["EPSG","4818"]]
???????????????????????????????????????????????????????????????????????????????
GEOGCS["WGS 72BE",
   DATUM["WGS 72 Transit Broadcast Ephemeris",
     SPHEROID["WGS 72", 6378135.0, 298.26, AUTHORITY["EPSG","7043"]],
     TOWGS84[0.0, 0.0, 1.9, 0.0, 0.0, 0.814, -0.07838062637389662],
     AUTHORITY["EPSG","6324"]],
   PRIMEM["Greenwich", 0.0, AUTHORITY["EPSG","8901"]],
   UNIT["degree", 0.017453292519943295],
   AXIS["Geodetic latitude", NORTH],
   AXIS["Geodetic longitude", EAST],
   AUTHORITY["EPSG","4324"]]

Its look like that ""S-JTSK (Ferro)" really don't have TOWGS84 parameters 
defined in the EPSG database. Or maybe there is some but the epsg-hsql plugin 
missed then. If you can find such parameter in the EPSG database or if you can 
send us by email a transformation path that Geotools should have found, it 
would 
be a bug in the referencing module that I would try to fix.

In the main time, you can use the LENIENT_DATUM_SHIFT hint for getting 
transformations even when the Bursa-Wolf parameters are missing.

        Martin

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