Hi Daniel,
please remember that if the ratio of your bbox and the ratio of your
width versus height in pixels, differs, the map will be stretched. That
could explain some of the behaviour. You need to make sure that the
values in your WMS request have the same ratio. I don't know if this is
the problem, but it could be a cause.
Proj.4 has a utility to reproject. The proj utilities also come with
MS4W. See also:
http://proj.maptools.org/man_cs2cs.html
Best regards,
Bart
Daniel Goetz wrote:
Hi,
thank you Frank, Trond and Ed for your help. I tried to use reporjected coordinates as
BBOX-values in my "new" WMS-GetMap-request (SRS=WPSG:4326) and it works now. I
got the new reprojected coordinates out of the GetCapabilities document (I took them out
of the LatLonBoundingBox paragraph in the GetCapabilities document):
<Layer queryable="1" opaque="0" cascaded="0">
<Name>VIEW_RWG_TBS</Name>
<Title>RWG_TM_NR</Title>
<SRS>EPSG:31468</SRS>
<SRS>EPSG:4326</SRS>
<LatLonBoundingBox minx="10.9905" miny="49.3319" maxx="11.2852"
maxy="49.5441" />
<BoundingBox SRS="EPSG:31468"
minx="4.42695e+006" miny="5.46647e+006" maxx="4.44806e+006"
maxy="5.48982e+006" />
<Style>
<Name>default</Name>
<Title>default</Title>
<LegendURL width="20" height="10">
<Format>image/png</Format>
<OnlineResource xmlns:xlink="http://www.w3.org/1999/xlink"; xlink:type="simple"
xlink:href="http://10.65.112.50/cgi-bin/mapserv.exe?map=/ms4w/apache/htdocs/WMS/WMS_BRWK.map&version=1.1.1&service=WMS&request=GetLegendGraphic&layer=VIEW_RWG_TBS&format=image/png"/>
</LegendURL>
</Style>
</Layer>
But I have two further questions:
When I do a WMS-GetMap-request in the "new" SRS (EPSG:4326) the map maserver sends back does not vary form the map mapserver generates when sending a
GetMap-request in the "original" SRS (EPSG:31468). I mean there is no deformation/distortion noticeable. But when I do a "normal" mapserver
mode=browse-request in my simple pan and zoom template and tell mapserver to reproject the data in EPSG:4326 (I do that by putting the PROJECTION-object in the
MAP-object of the .map-file to "init=epsg:4326" while the PROJECTION-objects in the LAYER-objects are still in the "origninal"
"init=epsg:31468" projection. Of course I change the EXTENT-parameters in the .map-file too. Am I doing right?) the returned map looks different
from the map genereated using the "original" projection. I mean that the reprojected map using mode=browse looks deformed/distorted compared to the
"original" not reprojected map.
The question is now: Why do the two maps (the reprojected one I get from the
WMS-GetMap-request and the reprojected map I get by a mode=browse request) differ in
their appearence (distortion) although I tell mapserver in both cases to reproject the
map to "epsg:4326"?
The secoond question is: As mentioned I got the "new" reprojeted coordinates for BBOX-values out of
the GetCapabilities document. But is there a program that could do coordinate transformation for me, so that
I am able to transform "epsg:31468" coordinates to "epsg:4326" coordinates?
OK, that's it. Thak you again for your helpful hints. And would be very nice of
you if you could help me further on with my problems/questions elucidated in
this email. Thank you so much.
regards
Daniel
-------- Original-Nachricht --------
Datum: Thu, 27 Jul 2006 09:22:21 -0400
Von: Ed McNierney <[EMAIL PROTECTED]>
An: [email protected]
Betreff: Re: [UMN_MAPSERVER-USERS] WMS and SRS
Daniel -
I think Frank's theory is likely to be correct, and that there is a
problem with the BBOX coordinates used in your new request. It sounds like the
changes you made are fine, although I think it is not necessary to add all
supported SRS systems to the metadata for each layer - just the MAP-level
metadata should be all you need to do.
Can you post the SRS= and BBOX= parameters you are using in your original
epsg:31468 request and in the new epsg:4326 requests?
- Ed
Ed McNierney
President and Chief Mapmaker
TopoZone.com / Maps a la carte, Inc.
73 Princeton Street, Suite 305
North Chelmsford, MA 01863
[EMAIL PROTECTED]
(978) 251-4242
-----Original Message-----
From: UMN MapServer Users List [mailto:[EMAIL PROTECTED] On
Behalf Of Daniel Goetz
Sent: Thursday, July 27, 2006 3:05 AM
To: [email protected]
Subject: [UMN_MAPSERVER-USERS] WMS and SRS
Hi coummunity,
I built up a littel WMS-server with umn-mapserver (local installation;
ms4w 2.1). The "original" projection of the single Layers is alway epsg:31468
(these are cartesian Gauß-Krüger-coordiantes). So I set the
PORJECTION-object of each LAYER and in the MAP-object to "init=epsg:31468". In
the
METADATA of the MAP-object as well as in the single LAYER-objects I defined
"wms_srs" as "EPSG:31468" as well. For testing purpose I did some
WMS-GetMap-Requests with "SRS=EPSG:31468" and everything went fine.
But now I want to make my WMS-service more interchangeable, so I want to
define some more SRSs in that the WMS should be able to be displayed. I want
to make it possible to "transform" (don't know the exact word in english)
the WMS from its original Projection to another SRS (e.g. WGS 84;
EPSG:4326). In my opinion this should be possible by adding another epsg-code
to the
METADATA. So my METADATA (both in the MAP and in the LAYERs-objects) look
like this: "wms_srs" "EPSG:31468 EPSG:4326".
But now every time I change the SRS block in my WMS-GetMap-request from
"SRS=EPSG:31468" to "SRS=EPSG:4326" mapserver returns a blank image. I even
tried to set the BBOX to latlon-coordinates when using "SRS=EPSG:4326" but
even this failed. I also testes other SRSs (both geographic ones and real
projections) but with no success.
Could anybody please give me some help or hints what to do and what went
wrong and why did this happen? I would be very glad and thankful. Thank you
so much.
regards
Daniel
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