[Qgis-user] Raster calculator difference evaluation

[Nicolas Cadieux]

Hi,
I would create a mask with raster A where any value = 1 and nodata = 0.  Then multiply the raster B by the mask. Anything that comes back as zero contains no data in raster A. 

Nicolas Cadieux
https://gitlab.com/njacadieux

> Le 3 oct. 2021 à 10:36, Davide Di Mauro <davide.dimauro at alluvium.com.au> a écrit :
> 
> 
> Hi all,
> I have two rasters.
> I need to output cells of one raster that are not present in the other. How would I go in order to achieve that using the raster calculator (i.e. avoiding Python)?
> My logic so far is:
> if A - B = A then output cells from A deriving from that evaluation and NoData everywhere else.
> The problem is that in the raster calculator I can only evaluate the subtraction and the equality does not evaluate in the same way of the subtraction, even if computed in a different instance.
> Is there a secret ingredient? Can my logic be rewritten differently? or am I way off?
>  
> Cheers
> Davide
>  
> Davide Di Mauro | Alluvium Consulting Australia
> GIS Specialist & Flood Modeller
> M  0422 634 107
> E  davide.dimauro at alluvium.com.au
> www.alluvium.com.au | Suite 12 - 36 Agnes St, Fortitude Valley - 4006| LinkedIn
> 
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>  
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