[fdo-trac] #723: Wrong No Data Value

[FDO]

#723: Wrong No Data Value
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   Reporter:  sgamperl      |       Owner:  gregboone                       
       Type:  defect        |      Status:  new                             
   Priority:  major         |   Milestone:  3.6.0                           
  Component:  WMS Provider  |     Version:  3.4.0                           
   Severity:  1             |    Keywords:  WMS, NullPixelValue, NODATAVALUE
External_id:                |  
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 The NullPixelValue Property of the OSGeo.FDO.Raster.IRaster interface is
 always 0 if i use the WMS Provider.

 I think the code in the function _getNullPixelValue() in FdoWMSImage.cpp
 is wrong.

 // determine the bits per pixel
 double null_val = m_bands[0]->GetNoDataValue(&bSuccess);
 if (!bSuccess)
       null_val = 0;

 If a palette is used in the WMS and then the first color in the palette
 would be the no data value. That's wrong.

 A NoDataValue of 0 is a valid value.
 It shouldn't be set in this function if bSuccess == false.

 From outside I can check with the raster.NullPixelValue.IsNull() function
 if it has a correct value.

 Is there a workaround for the problem?

-- 
Ticket URL: <http://trac.osgeo.org/fdo/ticket/723>
FDO <http://fdo.osgeo.org/>
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