There is something strange with Proj4 setting there. More details
below...
Le mardi 13 février 2007 à 07:24 +0100, Wim Blanken a écrit :
> So the proj string becomes: # Amersfoort / RD New
>
> <28992> +proj=sterea +lat_0=52.15616055555555 +lon_0=5.38763888888889
> +k=0.999908 +x_0=155000 +y_0=463000 +ellps=bessel +units=m
> +towgs84=565.2369,50.0087,465.658,-0.406857330322398,0.350732676542563,-1.8703473836068,4.0812
> +no_defs <>
>
>
> But Geoserver does not use these proj settings. It uses a WKT list.
> Has anybody any ideas about changing the settings below as that it is
> the same as the proj. string above?
>
> 28992=PROJCS["Amersfoort / RD
> New",GEOGCS["Amersfoort",DATUM["Amersfoort",SPHEROID["Bessel
> 1841",6377397.155,299.1528128,AUTHORITY["EPSG","7004"]],AUTHORITY["EPSG","6289"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.01745329251994328,AUTHORITY["EPSG","9122"]],AUTHORITY["EPSG","4289"]],PROJECTION["Oblique_Stereographic"],PARAMETER["latitude_of_origin",52.15616055555555],PARAMETER["central_meridian",5.38763888888889],PARAMETER["scale_factor",0.9999079],PARAMETER["false_easting",155000],PARAMETER["false_northing",463000],UNIT["metre",1,AUTHORITY["EPSG","9001"]],AUTHORITY["EPSG","28992"]]
You need to provide the TOWGS84 elements (aka "Bursa-Wolfs parameters"),
which is missing in WKT file. Alternatively, you can also drop the
"epsg-wkt" module (which is deprecated with Geotools 2.4 anyway) and use
"epsg-hsql" instead, which contains the needed Bursa-Wolfs parameters.
There is the WKT string as produces by the following command line:
java org.geotools.referencing.factory.epsg.DefaultFactory 28992
PROJCS["Amersfoort / RD New",
GEOGCS["Amersfoort",
DATUM["Amersfoort",
SPHEROID["Bessel 1841", 6377397.155, 299.1528128,
AUTHORITY["EPSG","7004"]],
TOWGS84[565.04, 49.91, 465.84, -0.40939438743923684,
-0.35970519561431136, 1.868491000350572, 0.8409828680306614],
AUTHORITY["EPSG","6289"]],
PRIMEM["Greenwich", 0.0, AUTHORITY["EPSG","8901"]],
UNIT["degree", 0.017453292519943295],
AXIS["Geodetic latitude", NORTH],
AXIS["Geodetic longitude", EAST],
AUTHORITY["EPSG","4289"]],
PROJECTION["Oblique Stereographic", AUTHORITY["EPSG","9809"]],
PARAMETER["central_meridian", 5.387638888888891],
PARAMETER["latitude_of_origin", 52.15616055555556],
PARAMETER["scale_factor", 0.9999079],
PARAMETER["false_easting", 155000.0],
PARAMETER["false_northing", 463000.0],
UNIT["m", 1.0],
AXIS["Easting", EAST],
AXIS["Northing", NORTH],
AUTHORITY["EPSG","28992"]]
You can just add the TOWGS84 element and ignore other new items like
AXIS[...], if you want to keep the same axis order.
Now the strange thing... Note that the TOWGS84 parameters in the above
WKT string (extracted from EPSG database) differ slightly from the ones
provided in the Proj4 string. The table below is extracted by Geotools
from the EPSG database for transformations from "EPSG:28992" to various
target datum. The Proj4 parameters look more closely to something like
"TO_EUROPEAN_1989[...]" than "TOWGS84[...]" parameters, but is not
identical neither. I wonder where Proj4 took their parameters.
╓────────────────────────────────────────────┬─────────┬────────┬─────────┬────────┬────────┬───────┬───────╖
║ Destination │ dx │ dy │ dz │
ex │ ey │ ez │ ppm ║
╟────────────────────────────────────────────┼─────────┼────────┼─────────┼────────┼────────┼───────┼───────╢
║ European Terrestrial Reference System 1989 │ 565,237 │ 50,009 │ 465,658 │
-0,407 │ -0,351 │ 1,870 │ 0,842 ║
║ World Geodetic System 1984 │ 565,040 │ 49,910 │ 465,840 │
-0,409 │ -0,360 │ 1,868 │ 0,841 ║
╙────────────────────────────────────────────┴─────────┴────────┴─────────┴────────┴────────┴───────┴───────╜
Martin
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