Re: [Qgis-user] new issue with raster calculator

[Bernd Vogelgesang]

Hi,
I have the impression that the raster calculator is some kind of an  
unloved child in this project:


Had the same issue posted a year ago, and it was marked as fixed:  
https://hub.qgis.org/issues/8619


Furthermore, the documentation (  
http://docs.qgis.org/2.6/en/docs/user_manual/working_with_raster/raster_calculator.html  
)is somewhat sparse, which leads to endless trial-and-error and a lot of  
frustration.


I avoid using it.

Cheers
Bernd

Am 18.05.2015, 15:07 Uhr, schrieb Giacomo Fontanelli  
:



Dear community

I have a raster layer with pixel values ranging from -8 to -11.

when I do "layer1@band1" * 0.1 I get a map with only 0 and Nan, instead
when I do "layer1@band1" / 10 I obtain the map with correct values.

What do I do wrong?

Thank you very much




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Re: [Qgis-user] new issue with raster calculator

[Nicolas Cadieux]

Hi,
Works for me.  Placing a "," rather that a "." decimal results in a 
"expression invalid" so that can't be it.  Are you really getting Nan?  
Use the "value plugin" to look at this or look at the histogram in layer 
properties.  Sometime it is just the image scaling that is off.  Send a 
sample file to test if it's still an issue.
Nicolas

Le 2015-05-18 09:04, Giacomo Fontanelli-2 [via OSGeo.org] a écrit :
> Dear community
>
> I have a raster layer with pixel values ranging from -8 to -11.
>
> when I do "layer1@band1" * 0.1 I get a map with only 0 and Nan, instead
> when I do "layer1@band1" / 10 I obtain the map with correct values.
>
> What do I do wrong?
>
> Thank you very much
>
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Re: [Qgis-user] new issue with raster calculator

[Albin Blaschka]

Am 18.05.2015 um 15:07 schrieb Giacomo Fontanelli:

Dear community

I have a raster layer with pixel values ranging from -8 to -11.

when I do "layer1@band1" * 0.1 I get a map with only 0 and Nan, instead
when I do "layer1@band1" / 10 I obtain the map with correct values.

What do I do wrong?

Thank you very much



Just a shot into the blue: A problem with decimal point vs. comma? What 
do you get if you try with 0,1 instead of 0.1?


greetings,
Albin

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[Qgis-user] new issue with raster calculator

[Giacomo Fontanelli]

Dear community

I have a raster layer with pixel values ranging from -8 to -11.

when I do "layer1@band1" * 0.1 I get a map with only 0 and Nan, instead
when I do "layer1@band1" / 10 I obtain the map with correct values.

What do I do wrong?

Thank you very much
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