[QGIS-Developer] Mesh netcdf NaN visualisation in QGIS?

[Aron Gergely]

Are you also able to load data via the GDAL driver?
If so you could then try to show nodata using raster styling.

e.g.: make sure that Nodata is not set to transparent: go to the 
raster's layer properties -> transparency, untick nodata value.
Then style in symbology settings.

Best regards,
Aron

On 04-09-2023 09:57, Richard Duivenvoorde via QGIS-Developer wrote:
> Hi,
>
> My colleague is creating netcdf as output of some other modelling 
> software, and viewing/styling it in QGIS.
>
> In some places the modelling software goes awry and produces NaN's in 
> de netcdf.
>
> Anybody an idea to create a visualisation (in QGIS) to find out WHICH 
> part/cell's contain a NaN?
>
> output of ncdump:
>   0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
> 0, 0,·
>     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, NaNf, NaNf, NaNf, 
> 0, 0,·
>     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
> 0, 0,·
>     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
> 0, 0,·
>     0, 0, 0, 0, 0, 0,
>
> Found: 
> https://github.com/lutraconsulting/MDAL/blob/master/mdal/frmts/mdal_netcdf.cpp#L100-L102
>
> So apparently in MDAL this becomes 
> "std::numeric_limits<double>::quiet_NaN"
>
> But how to find these in QGIS?
>
> Looking in Layer Styling I could use non-numbes (like None, NaN or 
> whatever) in the inputs.
> Same in Mesh calculator.
>
> Any idea appreciated!
>
> Regards,
>
> Richard Duivenvoorde
>
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-- 
Email Signature Kind Regards,

Aron Gergely
+31 (0) 6 38 70 97 66

*Rasterra* | www.rasterra.nl
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