[Qgis-user] Raster Calculator Error Questions

[Nicolas Cadieux]

Hi,
I have not used the raster calculator in a while but I am not sure about you use of the \.
Examples in the user manual (https://docs.qgis.org/3.16/en/docs/user_manual/working_with_raster/raster_analysis.html#raster-calculator) use this as examples.

("elevation at 1" < 50) * 1 + ("elevation at 1" >= 50) * 2

I would try (expression 1) OR (expression 2).  Layers names must be placed between quotes “”.

You could also update your QGIS version to 3.16.  

Nicolas Cadieux
https://gitlab.com/njacadieux

> Le 12 févr. 2021 à 09:09, Wanda Norman <wanda.mnorman2015 at gmail.com> a écrit :
> 
> 
> Greetings friends:
>  
> I am working on lesson 7.3.5 in the User Guide / Manual (QGIS 3.10) – Following along: Using the Raster Calculator.
>  
> I am having difficulty with the calculation formula as indicated below:
>  
> The manual states this formula should be used:
>                Aspect at 1 <=90 OR Aspect at 1 >= 270
> Which I am assuming is incorrect because a) I get an error when I run it; and b) when I set the parameters using the expression operators the formula looks like this:
>                “Aspect at 1” <=90 OR “Aspect at 1” >=270
> However, I still get the error:
> Error parsing formula
> Execution failed after 0.02 seconds
>  
> With some help – I then tried this formula
> \“Aspect at 1”\ <=90 OR \“Aspect at 1”\ >=270
> Which worked for this assignment.
>  
> However, moving on to lesson 7.3.6 – More criteria: which takes me to 21.12.2. Calculate slope (less than 2 and 5 degrees)
> I get the same error as above again.
>  
> I am steadily working my way through the Manual and would appreciate any help.  I am using QGIS version 3.10.9-A Coruna (64 bit) on a Windows PC.
>  
> Thank you!
> Wanda Norman
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