Mauro Bartolomeoli ha scritto: > We are working on an Italy Cadastre importer, and we are thinking to use > udig to view the produced data, so we are going to need a CRS to attach > to Cassini-Soldner projected data. > It's not widely tested and not very accurate (the error is in the order > of meters, compared to commercial software we use to convert to the same > data).
Interesting. Wondering if it's the math or the towgs84 params. Italy has the very sorry situation (not sure how common in other countries) that in order to have sub-meter precision on a local area transformation you need the TOWGS84 params _for that area_, usually contained in a document that can be bought by the militars. The 3 towgs84 params contained in the epsg database do not allow for a precision better than 4 meters, and unfortunately geotools is just picking one of them, I believe the one valid for Sardinia, so if you're reprojecting on the continental part, you'll get even bigger errors. (I'm reporting by memory, so I may be completely off on the magnitude of the errors or about the chosen towgs84 set of params). Cheers Andrea ------------------------------------------------------------------------- Check out the new SourceForge.net Marketplace. It's the best place to buy or sell services for just about anything Open Source. http://ad.doubleclick.net/clk;164216239;13503038;w?http://sf.net/marketplace _______________________________________________ Geotools-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/geotools-devel
