[Qgis-developer] QGIS + CRS:84

[Emmanuel Séguin]

Hello all,

We're experiencing a little glitch using QGIS with WMS 1.3.0 layer

The scenario : Open QGIS, Add WMS Layer, Connect to WMS to get 
capabilities, select layer, add layer. Result : No data displayed 
neither in the thumbnail nor in the main map window.

Here is the layer we're trying to display into QGIS :

<Layer>
   <Name>SCANDEP_PNG_IGNF_LAMB93</Name>
   <Title>ScanDEP IGN en PNG</Title>
   <Abstract>ScanDEP</Abstract>
   <KeywordList>
     <Keyword>ScanDEP</Keyword>
   </KeywordList>
   <CRS>IGNF:LAMB93</CRS>
   <CRS>epsg:2154</CRS>
   <CRS>IGNF:LAMBE</CRS>
   <CRS>epsg:4326</CRS>
   <CRS>CRS:84</CRS>
   <EX_GeographicBoundingBox>
     <westBoundLongitude>-7</westBoundLongitude>
      <eastBoundLongitude>12</eastBoundLongitude>
     <southBoundLatitude>40</southBoundLatitude>
     <northBoundLatitude>52</northBoundLatitude>
   </EX_GeographicBoundingBox>
   <BoundingBox CRS="IGNF:LAMB93" minx="57599" miny="5999999" maxx="1289601" maxy="7142400"/>
   <MinScaleDenominator>357.143</MinScaleDenominator>
   <MaxScaleDenominator>4.68114e+08</MaxScaleDenominator>
</Layer>


To try and understand why no data were displayed, I've intercepted the 
QGIS requests with Wireshark and here is what actually happens :

For the thumbnail :

http://domain.com/wms?
SERVICE=WMS
&VERSION=1.3.0
&REQUEST=GetMap
&BBOX=33.000000,-7.000000,52.000000,12.000000
&CRS=CRS:84
&WIDTH=32
&HEIGHT=32
&LAYERS=SCANDEP_PNG_IGNF_LAMB93
&STYLES=
&FORMAT=image/png
&TRANSPARENT=TRUE


For the map :

http://domain.com/wms?
SERVICE=WMS
&VERSION=1.3.0
&REQUEST=GetMap
&BBOX=40.002644,-7.000000,52.000000,12.000000
&CRS=CRS:84
&WIDTH=972
&HEIGHT=614
&LAYERS=SCANDEP_PNG_IGNF_LAMB93
&STYLES=
&FORMAT=image/png
&DPI=96
&TRANSPARENT=TRUE

=> QGIS requests are sent with the advertised CRS:84 but the BBOX are 
actually wrong (the axis order is lat/lon when it should be lon/lat).

However, if we define the SRS using the "Change..." button of the WMS 
layer window everything is working fine.

Is there a bug fix planned for this issue ?

Thanx in advance,

Manu

PS : Yeah i know "epsg" are in lower case ... maybe QGIS doesn't like it 
... but it's been a good way to spot a bug ;)

-- 
Emmanuel Séguin
SIEL - Pôle technique du Géoportail
Institut Géographique National
2/4, avenue Pasteur - 94165 Saint Mandé Cedex
Phone : +33 1.43.98.80.00 (ext : 72.21)
http://fr.linkedin.com/in/emmmanuelseguin