Interesting; we should talk this over with the referencing module maintainer and probably issue a bug report? Jean you were understanding the steps as I described them; apparently the information is not available :-(
The "equalsIgnoresMetadata" method is used internally by the CRS class as it tries to find a "match" for you. Jody On 18/05/2010, at 2:22 AM, [email protected] wrote: > I had the same problems with bursa wolf params for coordinate systems > in Austria and this ended in parsing my own wkt defenitions. > Afterwards, everything works fine. > > Quoting Jean Marie <[email protected]>: > >> >> Hi Jody >> >> I tried to debug from line : >> >> String code = CRS.lookupIdentifier( example, true ); // should be "EPSG:4230" >> >> and from >> >> CoordinateReferenceSystem crs = CRS.decode( code ); >> >> but I didn't come accross the method "equalsIgnoresMetadata" >> although this method is visible several times in CRS.java ; >> >> if you are talking about a method equalsIgnoresMetadata inside of >> CRS.java, I wonder from which method you get there ; >> I must miss something... >> >> by the way I noticed that CRS.java has a main class that can display >> the Bursa-Wolf parameters using parameter -bursawolfs >> in a command line >> >> unfortunately for "EPSG:27572" no Bursa-Wolf parameter are displayed >> (even if it requires gt-epsg-hsql-2.6.3.jar) ! >> here is the result : >> >> ??????????????????????????????????????????????????? >> ? Destination ? dx ? dy ? dz ? ex ? ey ? ez ? ppm ? >> ??????????????????????????????????????????????????? >> ??????????????????????????????????????????????????? >> >> in desperation, I took the Bursa-Wolf parameters from the >> spatialreference.org site which gives a correct result, >> namely TOWGS84[-168,-60,320,0,0,0,0] (and using only >> gt-referencing-2.6.3.jar) >> >> If I can really get the parameters from the debug process it would >> be reassuring >> >> thanks anyway >> >> Jean-Marie >> >> Subject: Re: [Geotools-devel] how to get Bursa-Wolf parameters in WKT strings >> From: [email protected] >> Date: Mon, 17 May 2010 20:29:01 +1000 >> CC: [email protected] >> To: [email protected] >> >> >> >> Hi Jean - we should keep this on the email list. >> Can you try the code example and step through it with a debugger? >> This should help explain why it will hep you.1. You parse the WKT >> into a CoordinateReferenceSystem2. You look for a matching >> CoordinateReferenceSystem coming out of the official EPSG database >> Inside that code it goes through and checks for a >> CoordinateReferenceSystem with the same values as yours; ignoring >> the metadata (such as name and description). The method is called >> "equalsIgnoresMetadata" if you are interested.3. It returns you a >> match ... and that match includes Bursa Wolf Parameters >> Jody >> On 17/05/2010, at 7:37 PM, Jean Marie wrote:Hi jody >> >> I had a look at the example given at : >> >> http://docs.codehaus.org/display/GEOTDOC/01+CRS+Helper+Class#01CRSHelperClass-SearchingforaCoordinateReferenceSystem >> >> I think you refer to the following code : >> ----- >> String code = CRS.lookupIdentifier( example, true ); // should be >> "EPSG:4230"CoordinateReferenceSystem crs = CRS.decode( code ); >> ------ >> >> well I don't know how this can help me ; >> >> you talked also about an "Equals" method that could assist me ; >> well I don't see how >> >> if you could give me some further details it would be helpfull >> as I don't know how to sort out this problem of String WKT >> which sometimes contains all parameters required and sometimes doesn't >> >> thanks a lot >> >> Jean-Marie >> >> >> Subject: Re: [Geotools-devel] how to get Bursa-Wolf parameters in WKT strings >> From: [email protected] >> Date: Thu, 13 May 2010 08:35:11 +1000 >> CC: [email protected] >> To: [email protected] >> >> Hi Jean >> Here is what I kind of do; I use the CoordinateReferenceSystem >> created my WKT to look up the "Real" CoordinateReferenceSystem >> produced by the EPSG database (which is much more complete). >> There is an "Equals" method that ignores metadata to assist you with >> this; and because I find CoordinateReferenceSystem stuff difficult >> to manage by hand there should be a helper method ... >> Yes there is - indeed it is one of the use-cases covered by the user >> >> guide:-http://docs.codehaus.org/display/GEOTDOC/01+CRS+Helper+Class#01CRSHelperClass-SearchingforaCoordinateReferenceSystem >> Cheers, Jody >> On 13/05/2010, at 3:15 AM, Jean Marie wrote:Hello >> >> my purpose is to get a list of projection systems described in a WKT >> format (so using gt-epsg-hsql-2.6.3) ; >> and then to use these WKT representations to achieve tranformations >> using only >> the library gt-referencing-2.6.3.jar >> >> to get these WKT strings I use the following code : >> >> CoordinateReferenceSystem crsSrc = >> ReferencingFactoryFinder.getCRSAuthorityFactory("EPSG", >> null).createCoordinateReferenceSystem(EPSG); >> and then crsSrc.toWKT() gives the WKT specification for EPSG >> >> I took 3 WKT representations for respectively EPSG = "EPSG:4326", >> EPSG = "EPSG:2056" and EPSG = "EPSG:27572" >> then I created for each one a CoordinateOperationFactory object to >> carry out 2 transformations : >> one from 4326 to 2056 (Switzerland) et the other from 4326 to 27572 >> (France) using the WKT strings >> >> I noticed that the WGS84 to Swiss transformation is correct, >> while the WGS84 to French transformation generates an error saying >> that Bursa-Wolf parameters are required ; >> >> I would like to know how to sort out this problem as I need accurate results >> and I cannot afford to use the following code involving some >> transformation errors: >> >> CRS.findMathTransform(crsSrc, crsDest, true) >> >> is it possible to get Bursa-Wolf parameters in each WKT representation ? >> >> thanks a lot >> >> Jean-Marie >> >> Vous voulez protéger votre vie privée ? 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