Thanks Martin,
I have created a new WKT and used the following code :
CRSFactory crsFactory = FactoryFinder.getCRSFactory(null);
targetCRS = crsFactory.createFromWKT(wkt);
My WKT is :
"PROJCS[\"NTF (Paris) / Lambert zone II\", "
+ "GEOGCS[\"NTF (Paris)\", "
+ "DATUM[\"Nouvelle Triangulation Francaise (Paris)\", "
+ "SPHEROID[\"Clarke 1880 (IGN)\", 6378249.2, 293.4660212936269], "
+ "TOWGS84[-168,-60,320,0,0,0,0]], "
+ "PRIMEM[\"Paris\", 2.5969213], "
+ "UNIT[\"grade\",0.015707963267948967], "
+ "AXIS[\"Longitude\",EAST], "
+ "AXIS[\"Latitude\",NORTH]], "
+ "PROJECTION[\"Lambert Conic Conformal (1SP)\"], "
+ "PARAMETER[\"semi_major\", 6378249,2], "
+ "PARAMETER[\"semi_minor\", 6356515], "
+ "PARAMETER[\"central_meridian\", 0.0], "
+ "PARAMETER[\"latitude_of_origin\", 52.0], "
+ "PARAMETER[\"scale_factor\", 0.99987742], "
+ "PARAMETER[\"false_easting\", 600000.0], "
+ "PARAMETER[\"false_northing\", 2200000.0], "
+ "UNIT[\"metre\",1.0], "
+ "AXIS[\"x\",EAST], "
+ "AXIS[\"y\",NORTH]]";
The transformation produces an accurate and correct result.
I also send a request to the EPSG in order to add this transformation in the
next release of the database.
Regards,
Loïc
----- Original Message -----
From: "Martin Desruisseaux" <[EMAIL PROTECTED]>
To: "Loïc MAZE" <[EMAIL PROTECTED]>
Cc: <geotools-gt2-users@lists.sourceforge.net>
Sent: Thursday, May 11, 2006 2:21 AM
Subject: Re: [Geotools-gt2-users] CRS transformation not accurate
Loïc MAZE a écrit :
The only data which can be interesting is about the transformation : NTF
=> WGS84. I don't know if it is useful for Geotools or not.
The following command line:
java -classpath gt2-epsg-access-2.3-SNAPSHOT.jar
org.geotools.referencing.factory.epsg.DefaultFactory 4275
show the following:
GEOGCS["NTF",
DATUM["Nouvelle Triangulation Francaise",
SPHEROID["Clarke 1880 (IGN)", 6378249.2, 293.4660212936269,
AUTHORITY["EPSG","7011"]],
TOWGS84[-168.0, -60.0, 320.0, 0.0, 0.0, 0.0, 0.0],
AUTHORITY["EPSG","6275"]],
PRIMEM["Greenwich", 0.0, AUTHORITY["EPSG","8901"]],
UNIT["degree", 0.017453292519943295],
AXIS["Geodetic latitude", NORTH],
AXIS["Geodetic longitude", EAST],
AUTHORITY["EPSG","4275"]]
So its look like that a TOWGS84 element is defined for EPSG:4275, but not
for EPSG:27572 (even if they use the same spheroid - EPSG seems to still
consider them as two different datum, not sure why).
You may try the following:
FactoryFinder.getCRSFactory(null).parseWKT(wkt);
where wkt is:
PROJCS["NTF (Paris) / Lambert zone II",
GEOGCS["NTF (Paris)",
DATUM["Nouvelle Triangulation Francaise (Paris)",
SPHEROID["Clarke 1880 (IGN)", 6378249.2, 293.4660212936269,
AUTHORITY["EPSG","7011"]],
TOWGS84[-168.0, -60.0, 320.0, 0.0, 0.0, 0.0, 0.0],
AUTHORITY["EPSG","6807"]],
PRIMEM["Paris", 2.5969213, AUTHORITY["EPSG","8903"]],
UNIT["grade", 0.015707963267948967],
AXIS["Geodetic latitude", NORTH],
AXIS["Geodetic longitude", EAST],
AUTHORITY["EPSG","4807"]],
PROJECTION["Lambert Conic Conformal (1SP)", AUTHORITY["EPSG","9801"]],
PARAMETER["central_meridian", 0.0],
PARAMETER["latitude_of_origin", 52.0],
PARAMETER["scale_factor", 0.99987742],
PARAMETER["false_easting", 600000.0],
PARAMETER["false_northing", 2200000.0],
UNIT["m", 1.0],
AXIS["Easting", EAST],
AXIS["Northing", NORTH],
AUTHORITY["EPSG","27572"]]
i.e. the output of java [...] DefaultFactory 27572 with the TOWGS84
element copied from java [...] DefaultFactory 4275. I'm really not sure
that it is okay; lets see if the output is better.
Martin.
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