Hi Simon,
Do you mean that sometimes EPSG database could be wrong (even for very usual
SRS like WGS84)???
Here is the logger ouput:
INFO [main] (TestFeatureTransforming.java:24): WGS84: GEOGCS["WGS 84",
DATUM["WGS_1984",
SPHEROID["WGS 84", 6378137.0, 298.257223563, AUTHORITY["EPSG","7030"]],
AUTHORITY["EPSG","6326"]],
PRIMEM["Greenwich", 0.0, AUTHORITY["EPSG","8901"]],
UNIT["degree", 0.017453292519943295],
AXIS["Lon", EAST],
AXIS["Lat", NORTH],
AUTHORITY["EPSG","4326"]]
INFO [main] (TestFeatureTransforming.java:25): Lambert2: 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", 2.33722917, AUTHORITY["EPSG","8903"]],
UNIT["grade", 0.015707963267948967],
AXIS["Lon", EAST],
AXIS["Lat", NORTH],
AUTHORITY["EPSG","4807"]],
PROJECTION["Lambert_Conformal_Conic_1SP"],
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["x", EAST],
AXIS["y", NORTH],
AUTHORITY["EPSG","27572"]]
It looks pretty "normal" doesn't it?
And you're right, my lat is ~43.0 and lon is ~7.0 but if I try to transform
Coordinate(43, 7), I have totally wrong values. That's why I used lon/lat
instead of lat/lon wich give me realistic values (but not accurate). In these
WKTs longitudes are declared before latitudes. Is it what you called "wrong
axis order"?
Anyway I don't see how this axis order issue could explain the imprecision...
Thanks, Vincent.
-----Message d'origine-----
De : Martin Desruisseaux [mailto:[EMAIL PROTECTED]
Envoyé : mardi 17 avril 2007 17:12
À : zze-M2S FRISON V ext RD-BIZZ-SOP
Cc : [email protected]
Objet : Re: [Geotools-gt2-users] WGS84 to Lambert2e transforming
zze-M2S FRISON V ext RD-BIZZ-SOP a écrit :
> I'm trying with the usual EPSG code 4326 for WGS84 and 27572 for
> Lambert2e but the result is not accurate at all : the shift is around
> 1 km for the latitude and more than 19 kms for the longitude!
Watchout for axis order. Sound like that a majority of "Geotools
transformations are not accurate" emails on geotools users mailing list are
caused by wrong axis order.
> logger.info("WGS84: " + crsWGS84.toWKT());
What do you get? "AXIS["Geodetic latitude", NORTH], AXIS["Geodetic longitude",
EAST]" or the converse?
> Coordinate c1 = new Coordinate(7.0, 43.0);
If the logger printed latitude first, then you probably want Coordinate(43, 7)
(assuming you live in Europe).
Martin
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