[Mapserver-users] WMS client - multiple entries in "wms_srs"
havard.tveite at nlh.no
Thu Feb 26 12:59:19 EST 2004
I finally found out the cause of my problems.
On my platform, in order for Mapserver to be able to determine
that the map output projection is in the "wms_srs" list (and
choose that projection when requesting the WMS layer), the map
output projection has to be specified using lowercase, that is
"init=epsg:32633" and *not* "init=EPSG:32633".
At the same time, the projection name in the "wms_srs" list
has to be specified using upper case, that is
"wms-srs" = "EPSG:4326 EPSG:32633 ..."
"wms-srs" = "epsg:4326 epsg:32633 ..."
(I do not use a PROJECTION object in the WMS layer specification)
I also had to make two copies of the proj.4 epsg file. One called
EPSG and the other epsg!
Is it only me?
Daniel Morissette wrote:
> Havard Tveite wrote:
>> Using recent versions of Mapserver CVS, Proj.4, ... I am a little
>> confused as to the the use of "wms_srs" in the METADATA of a WMS-layer.
>> CONNECTIONTYPE WMS
>> "wms_srs" "EPSG:4326 EPSG:32633 EPSG:27394 EPSG:4267 EPSG:4269"
>> It seems to me that the first entry on the "wms_srs" list is
>> always choosen by Mapserver when doing the WMS request.
>> I thought that the point of having a list in "wms_srs" was that
>> Mapserver could choose among these projections depending on the
>> projection of the output map.
>> This way, raster reprojection could in many cases be avoided,
>> producing nicer output maps.
>> What is the point of having a list of projections in "wms_srs"?
>> Is it for future use?
> That's right, the wms_srs contains a list of SRS supported by the remote
> WMS server, and MapServer will choose the one that matches the map
> output projection if it can. If it can't find a match, then it falls
> back on using the first one and reprojects the raster image that it gets
> from the remote WMS.
> If the first one is always used, it could be that the output map
> projection doesn't match any of the EPSG codes that are in your list.
> Also note that MapServer can't do reverse lookups of EPSG numbers, so if
> you define your map's output projection using the native PROJ parameters
> (e.g. "proj=..." "lat_0=..."lon_0= ....) then MapServer won't be able to
> match that to an EPSG code: you have to use "init=epsg:xxxx" as your
> projection definition.
> Of course there is always the possibility that a bug was introduced in
> the recent code???
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