thanks a lot Jody
at it is written for findMathTransform that you refer to :
"this method will not throw a "Bursa-Wolf parameters required"
exception during datum shifts if the Bursa-Wolf paramaters"
that suits me meanwhile I find those parameters :)
jean-Marie
Subject: Re: [Geotools-gt2-users] Bursa-Wolf parameters required for EPSG 2062
even when accessing EPSG database
From: [email protected]
Date: Sat, 22 May 2010 10:03:29 +1000
CC: [email protected]
To: [email protected]
In the CRS utility class there is also a method to get a math transform where
you can set lenient to true; this tells it to proceed even if the correct
transform parameters are available.
Jody
On 19/05/2010, at 11:44 PM, Jean Marie wrote:Hello Jody
I go back over spain mainland EPSG which is 2062 ;
I notice that even if I use the library gt-epsg-hsql-2.6.3.jar (so the EPSG
database),
I am notified that Bursa Wolf are required !!
is there a pb with the connection to the EPSG database ?
(I tried other ESPG codes without any pb such as for instance French lambert
codes)
my following code is quite simple :
EPSGsrc="EPSG:4326";
EPSGdst="EPSG:2062";
Longitude=-3.015; Latitude=39.89;
CoordinateReferenceSystem crsSrc =
ReferencingFactoryFinder.getCRSAuthorityFactory("EPSG",
null).createCoordinateReferenceSystem(EPSGsrc);
CoordinateReferenceSystem crsDest =
ReferencingFactoryFinder.getCRSAuthorityFactory("EPSG",
null).createCoordinateReferenceSystem(EPSGdst);
CoordinateOperation op = coFactory.createOperation(crsSrc, crsDest);
MathTransform mathtransform = op.getMathTransform();
.....
the error happens at line "op = coFactory.createOperation(crsSrc, crsDest);"
org.opengis.referencing.operation.OperationNotFoundException: Les paramètres de
Bursa Wolf sont requis.
at
org.geotools.referencing.operation.DefaultCoordinateOperationFactory.createOperationStep(DefaultCoordinateOperationFactory.java:1072)
at
org.geotools.referencing.operation.DefaultCoordinateOperationFactory.createOperationStep(DefaultCoordinateOperationFactory.java:1165)
at
org.geotools.referencing.operation.DefaultCoordinateOperationFactory.createOperationStep(DefaultCoordinateOperationFactory.java:882)
at
org.geotools.referencing.operation.DefaultCoordinateOperationFactory.createOperationStep(DefaultCoordinateOperationFactory.java:965)
at
org.geotools.referencing.operation.DefaultCoordinateOperationFactory.createOperation(DefaultCoordinateOperationFactory.java:243)
at
org.geotools.referencing.operation.BufferedCoordinateOperationFactory.createOperation(BufferedCoordinateOperationFactory.java:254)
at TestGeoTools.transformEPSGsrcEPSGdst(TestGeoTools.java:98)
where line 98 corresponds to "CoordinateOperation op =
coFactory.createOperation(crsSrc, crsDest);"
do you have an idea about where does the problem come from ?
thanks in advance
Jean-Marie
Subject: Re: [Geotools-gt2-users] [Geotools-devel] how to get Bursa-Wolf
parameters in WKT strings
From: [email protected]
Date: Wed, 19 May 2010 11:30:33 +1000
CC: [email protected]
To: [email protected]
On 19/05/2010, at 12:18 AM, Jean Marie wrote:Thanks Jody for your suggestion
Did the code example on that page work for you?
at present, I just need a dozen of WKT strings but I already notice that,
sometimes , it is hard to find the Bursa-Wolf parameters ; as I told you is
that I must use a light library (gt-referencing-2.6.3.jar)
And I always remind you gt-referencing does not do anything on its own :-) You
need to feed i some definitions as well ... but I understand you do not want to
use a database.
for example if I consider Spain mainland the corresponding EPSG code is 2062
and there is no TOWGS84 parameters in the WKT string ;
http://spatialreference.org/ref/epsg/2062/ doesn't specify any TOWGS84[..]
string as well
as Geotools requires Bursa-Wolf parameters to work (when using just
gt-referencing-2.6.3.jar), is there an official site providing them?
The EPSG database is the official site (http://www.epsg.org/) who distribute
their data in an Access database. Sometimes individual countries also provide
official definitions as well). We set up GeoTools so you can configure it as
needed for your data.
if they are not required, is there a "trick" to set TOWGS84[..] to default
values ?
I am afraid all these numbers mean something and should be defined by a
standards agency (as they represent an agreement between map makers).
note : even when using gt-epsg-hsql-2.6.3.jar I have an error at :
op = coFactory.createOperation(crsSrc, crsDest); // crsSrc created from the WKT
string (4326), crsDest created from the WKT string (2062) saying that
Bursa-Wolf parameters are required...
I have another remark regarding the WKT format :
if I use the OGC wkt definitions given by the site spatialreference.org with
Geotools, none of them works fine (at least those I tried) ; the results are
wrong (even if I invert latitude and longitude...)
does it mean that the WKT format depends on the tools that processes it ?
Not sure about that; there are many flavours of WKT (mostly it is organisations
like Oracle that modify things a bit). There is a specific osgeo org mailing
list on this topic (making sure the coordinate reference systems work well
between projects).
Jody
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