Projection problem Mapserver/Geoserver/Geotools

Tue Feb 13 06:22:47 EST 2007

Dag Barend,

Hope everything is well, thanx for your answer!
I tried the Double_Stereographic yesterday already in Geoserver 1.4.0 it did
not work.
I downloaden the betaversion of Geoserver 1.5. This uses an other geotools
library for epsg namely the hsql version. Now it works out of the box.
I just got a mail from Andrea Aime who also advices to use Geoserver 1.5 as
it uses a more recent library of EPSG.

Here is his answer:

---------------------------

Geoserver 1.4.0 and older uses a WKT list that misses the TOWGS84
parameters, 1.5.0 onwards (you can test 1.5.0rc1 if you wish) uses the full
EPSG database, and the equivalent WKT looks like:

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 longitude", EAST],
     AXIS["Geodetic latitude", NORTH],
     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"]]

The missing parameters may account for the positioning errors you're
experiencing. About adding a custom projection, it's unfortunately not easy
in Geoserver, but here are some guidelines:

http://docs.codehaus.org/display/GEOSDOC/Custom+projection+definition+in+Geo
server

Anyways, I'd suggest you try out Geoserver 1.5.0rc1, hopefully having the
Bursa Worlf parameters around will fix your issue.

-----------------------------------------

Best regards,

Wim Blanken

-----Oorspronkelijk bericht-----
Van: Barend Köbben [mailto:kobben at itc.nl] 
Verzonden: dinsdag 13 februari 2007 12:07
Aan: Wim Blanken
Onderwerp: RE: [UMN_MAPSERVER-USERS] Projection problem
Mapserver/Geoserver/Geotools

Dag Wim,

The thing to change is the PROJECTION. The same as changing in proj.4 the
"stere" to "sterea". This changes the projection from oblique stereographic
to double stereographic. 

Altough I have no documentation of the WKT format used by Geoserver, my
educated guess (based on how ArcGIS does it, that uses a WKT description
also), change:
PROJECTION["Oblique_Stereographic"]
to 
PROJECTION["Double_Stereographic"]

--
Barend Köbben
International Institute for Geo-information 
Sciences and Earth Observation (ITC) 
PO Box 6, 7500AA Enschede (The Netherlands)
ph: +31 (0)53 4874253; fax: +31 (0)53 4874335

> -----Original Message-----
> From: UMN MapServer Users List 
> [mailto:MAPSERVER-USERS at LISTS.UMN.EDU] On Behalf Of Wim Blanken
> Sent: dinsdag 13 februari 2007 7:24
> To: MAPSERVER-USERS at LISTS.UMN.EDU
> Subject: [UMN_MAPSERVER-USERS] Projection problem 
> Mapserver/Geoserver/Geotools
> 
> Hello List,
> 
>  
> 
> Maybe a bit off topic but I cannot choose one simple list for 
> this one.....
> 
>  
> 
> The following projection problem. In the Netherlands we have 
> a projection system that is based on double_stereographic (sterea).
> 
> In the proj list there was a flaw with the settings for the 
> EPSG:28992 code. I did not see it until I played around with 
> google earth in combination with mapservices.
> 
> The alignment is wrong (about 80 meters north and twenty east)
> 
> I believe Jan Hartman from the Netherlands also encountered 
> this problem. In mapserver It can easily be repaired by 
> changing the +proj=stere with +proj=sterea.   
> 
>  
> 
> 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,-0.406857330322398,0.3507326
> 76542563,-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? By changing 
> the false easting and northing parameters I can align them 
> reasonably good., But I think that is not the solution. Is it?
> 
>  
> 
>  
> 
> 28992=PROJCS["Amersfoort / RD 
> New",GEOGCS["Amersfoort",DATUM["Amersfoort",SPHEROID["Bessel 
> 1841",6377397.155,299.1528128,AUTHORITY["EPSG","7004"]],AUTHOR
> ITY["EPSG","6289"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","890
> 1"]],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"]],AU
> THORITY["EPSG","28992"]]
> 
>  
> 
>  
> 
> Greetings,
> 
>  
> 
> Wim Blanken
> 
> The Netherlands
> 
> 

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