I want to understand Mesh Calculator in QGIS 3.8.3 to make calculation between two variables of a NetCDF file. Each of these variables has [lon, lat, time] dimensions. The calculation is done smoothly (which is suspiciously amazingly quick) and produces a binary file with (.dat) extension.

This dat file is probably meant for hydrodynamic modelling software but I cannot access them.

Is there a way to read this dat file by QGIS, or convert it to other formats for further analysis?

[Edit] ... Poor choice of word. As commented by Gabriel De Luca, it works lightning fast.

  • From QGIS 3.12 you are able to choose the output driver/format in the mesh calculator for your results Commented Feb 4, 2020 at 13:16

1 Answer 1


You can add it as a new dataset in the source layer through the Assign Extra Dataset to Mesh button, in the Source tab of the layer properties.


The Dataset will be added to the layer, but not saved in the layer file. It remains as a group of data in a separate file.

This test was made with a grib file. The algebra was just a weather condition.


  • Thanks @Gabriel De Luca ! That works (=^ ^=)...... (Sorry for this late reply. I had been struggling to export them in one nc file then... and given up finally).
    – Kazuhito
    Commented Oct 23, 2019 at 9:33
  • You`re welcome, @Kazuhito! Review the temporary information. My original data has a 3 hour step and it seems that this information was lost in algebra. Or maybe I made a mistake, it was a test. And I was also surprised how quickly the operation was performed! Commented Oct 23, 2019 at 10:08

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