Projection trouble

[Arnulf Christl]

Hi,
we experience a strange offset when overlaying the same data as WMS maps
with MapServer versions 4.0.1 and 4.4.1.

*4.0.1 server*
Windows 2000: SP4
IIS: 5
proj: came with 4.0.1
gd: came with 4.0.1
gdal: came with 4.0.1
Cap URL:
http://wms.ccgis.de/umn/bin/mapserv.exe?map=d:/umn/germany.map&SERVICE=WMS&REQUEST=GetCapabilities&VERSION=1.1.0
Data: local shape files in EPSG:4326 projected to EPSG:31467

*4.4.1 server*
FreeBSD: 4.10
Apache: 1.3.33
proj: 4.4.9
gd: 2.0.33
gdal: 1.2.1
Cap URL:
http://wms1.ccgis.de/cgi-bin/mapserv?map=/data/umn/germany_demo/germany_demo.map&VERSION=1.1.1&REQUEST=GetCapabilities&SERVICE=WMS
Data: the same shape files as above (WGS84) but dumped to
PostgreSQL/PostGIS (and also projected to EPSG:31467).

The problem does not seem to result from MapServer but from proj?

You can have a look at the problem here:
http://www.mapbender.org/demoserver.html

Zoom in to a scale of 1:100,000 or less to see the post code areas. They
overlap with an x-offset (north):
in northern Germany 190m
in central Germany 145m
in southern Germany 100m

The y-offset (east) is:
in western Germany 45m
in eastern Germany 125m

That resembles a lot to a datum shift which we stumbled accross (years
ago) when reading GPS EPSG:4326 WGS84 data directly into the database
and overlaying it with Gauss-Kruger EPSG:31467 (Bessel projection).

What has been changed and what impact does it have on projects which
overlay other data?

Best regards, Arnulf.

--
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Arnulf B. Christl
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http://www.ccgis.de
http://www.mapbender.org
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