Mapserver WMS client reprojects latlonboundingbox

[Bart van den Eijnden]

Hi list,

today we ran into a strange problem with Mapserver WMS client, when
zooming into a Demis WMS layer, Mapserver WMS client did not want to
render a layer, it did not even try to request the layer. Our application
operates in EPSG:28992 (Netherlands).

This is the important part of the WMS capabilities:

<LatLonBoundingBox minx="-180" miny="-90" maxx="180" maxy="90"/>
<BoundingBox SRS="EPSG:28992" minx="48443.3472125024"
miny="404023.309341862" maxx="144763.347212502" maxy="484658.309341862"/>

After a little digging in the code, I found something strange in
mapwmslayer.c:

// Reproject latlonboundingbox to the selected SRS for the layer and
// check if it overlaps the bbox that we calculated for the request
msProjectRect(&(map->latlon), &(lp->projection), &ext);

So what it is gonna do, is reproject -180,-90,180,90 into the Dutch RD
system, which is not valid outside of Netherlands :)

This is strange since it could easily use the other BoundingBox (for
EPSG:28992) specified in the WMS capabilities. It should only try to
reproject if a WMS service would not provide the "native" boundingbox in
my opinion.

But ofcourse one can argue that the Demis WMS service did not provide
correct/precise values for the LatLonBoundingBox ....

I have filed bug 1295 though about this:
http://mapserver.gis.umn.edu/bugs/show_bug.cgi?id=1295

Best regards,
Bart

PS This is the MAP file definition used:

  LAYER
    CONNECTION "http://myserver/wms/wms.asp?wms=TOPOFOTO&"
    CONNECTIONTYPE WMS
    DEBUG ON
    DUMP TRUE
      METADATA
        "wms_srs"       "EPSG:28992"
        #"wms_latlonboundingbox"        "-180 -90 180 90"
        "wms_name"      "Luchtfoto"
        "wms_formatlist"        "image/png,image/jpeg,image/gif,image/bmp,image/swf"
        "wms_format"    "image/png"
        "wms_boundingbox"       "EPSG:28992 48443.34766 404023.3125 144763.34375
484658.3125"
        "wms_server_version"    "1.1.1"
        "wms_title"     "Luchtfoto"
      END
    NAME "demis-Luchtfoto"
    PROJECTION
      "init=epsg:28992"
    END
    SIZEUNITS PIXELS
    STATUS ON
    TEMPLATE "blank.html"
    TOLERANCE 0
    TOLERANCEUNITS PIXELS
    TYPE RASTER
    UNITS METERS
  END