Andrea Aime probaly wrote: > Andrea Antonello ha scritto: >> Hi, I send this to both geotools and udgi, since I assume this is a >> geotools issue, but I have problems with the udig behaviour regarding >> this. >> >> When I try to reproject from (example) WGS84 4326 to Gauss Boaga 3003 I >> get an exception for the missing bursa wolf paramas. If, as I >> understand, these are the towgs parameters, I feel it is ok. At that >> point udig should however ask for them, right? I should be able to >> supply them if I have them. Probably already in the creation of a >> workspace in a particular projection? >> >> How does Udig deal with it, since it reprojects me the feature layer >> without asking anything from the above two projections and giving no >> problems? What does it do that can't be done otherwise? > > Probably uDig asks for a lenient transform, that is, one that tries to > do without the bursa wolf parameters.
Alright, I assume you're right. To the UDig list, how is that done? > As for providing the parameters, it depends on which version of geotools > you're using. I'm on udig 1.1.x, I'm not sure right now, I'll check. > On 2.2.x you have to edit the property file that backs the epsg-wkt > referencing authority and put the towgs84 params in the relevant wkt > definitins. > On 2.3.x, you're out of luck (in Geoserver we have our custom solution). > On trunk, epsg-wkt has been deprecated and we suggest to use epsg-hsql > instead, that has fuller information about CRS systems (such as area > of validity, and towgs parameters for more CRS afaik), and happily > the towgs parameters are included out of the box, here is the > wkt definition I get from Geoserver (which already uses the official > EPSG database): > > PROJCS["Monte Mario / Italy zone 1", > GEOGCS["Monte Mario", > DATUM["Monte Mario", > SPHEROID["International 1924", 6378388.0, 297.0, > AUTHORITY["EPSG","7022"]], > TOWGS84[-50.2, -50.4, 84.8, -0.69, -2.012, 0.459, > -5.791915759418465], > AUTHORITY["EPSG","6265"]], > PRIMEM["Greenwich", 0.0, AUTHORITY["EPSG","8901"]], > UNIT["degree", 0.017453292519943295], > AXIS["Geodetic longitude", EAST], > AXIS["Geodetic latitude", NORTH], > AUTHORITY["EPSG","4265"]], > PROJECTION["Transverse Mercator", AUTHORITY["EPSG","9807"]], > PARAMETER["central_meridian", 9.0], > PARAMETER["latitude_of_origin", 0.0], > PARAMETER["scale_factor", 0.9996], > PARAMETER["false_easting", 1500000.0], > PARAMETER["false_northing", 0.0], > UNIT["m", 1.0], > AXIS["Easting", EAST], > AXIS["Northing", NORTH], > AUTHORITY["EPSG","3003"]] According to the above, this is optimized for Sicily even if the last parameter is different between yours and the one GRASS supplies: rome40 "towgs84=-104.1,-49.1,-9.9,0.971,-2.917,0.714,-11.68" "Italy (Peninsular Part)" "Accuracy 3-4m" rome40 "towgs84=-168.6,-34.0,38.6,-0.374,-0.679,-1.379,-9.48" "Italy (Sardinia)" "Accuracy 3-4m" rome40 "towgs84=-50.2,-50.4,84.8,-0.690,-2.012,0.459,-28.08" "Italy (Sicily)" "Accuracy 3-4m" How is that dealth with? The dialog shows 3 projections of the same type defining also the optimized region? > About asking interactively, there is no way to alter a CRS definition > once it's build, so it simply does not make sense to provide an > interactive dialog. I don't understand you exactly. When you use reprojection for calculus and not just for visualization, things can get bad if the system does what it wants without asking. So when I create a map from a shapefile, why shouldn't the system ask for the proper values, if there is ambiguity? If the user doesn't know, it can get back to a lenient tranform. Andrea ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ Geotools-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/geotools-devel
