[Qgis-developer] How to load a colour table on a raster, programmatically (in python)?

[Peter Ersts]

On 08/05/2010 03:08 PM, Benoit de Cabissole wrote:
> I've implemented the code following your suggestions, but it throws the
> following error:
>
> ==================================================================
> Traceback (most recent call last):
>    File "C:\Documents and
> Settings\Benoit/.qgis/python/plugins\bcccoltbl\cdlgTBL.py", line 373, in
> accept
>      self.theLayer.rasterShader().setColorRampItemList(theTBL)
> AttributeError: 'QgsRasterShader' object has no attribute
> 'setColorRampItemList'
>    

Sorry Benoit. I kind of gave you the short hand version. 
RasterLayer.rasterShader() returns the base class of QgsColorRampShader 
which is QgsRasterShader() you will have to cast the base class to type 
QgsColorRampShader, but don't even know if that is possible in python.

However, there is another way, You could create your own instance of a 
QgsColorRampShader and pass that to the raster layer using
 >>yourColorRampShader = QgsColorRampShader()
 >>yourColorRampShader.setColorRampItemList( YourList )
 >>RasterLayer.setRasterShaderFunction( yourColorRampShader )

If you take this approach, you no longer have to call 
RasterLayer.setColorShadingAlgorithm().

That should do it. I don't do much python coding, so i may not be able 
to highlight all of the differences between the python and c++ approach.

-pete

-- 
====================================
Peter J. Ersts, Software Developer
American Museum of Natural History
Center for Biodiversity and Conservation
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Web: http://cbc.amnh.org

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