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I want to create a flow vector NetCDF data from two .tif raster, one representing X-velocity and another representing Y-velocity component. Both raster groups have identical spatial extent. I have converted each raster to NetCDF in ArcGIS and then merged it using NCO tool (ncecat). I had hoped I can symbolize the resulting NetCDF data as a vector, using arrows in QGIS but it is not recognized as a vector layer.

So, my question is how can I create a flow vector NetCDF data from two velocity components rasters (or from velocity magnitude and flow direction rasters) using NCO tools or Python? Is there any other way to do it beside these two?

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  • Not a direct answer to your question; it seems you have tried to read the NetCDF as a vector layer. QGIS can handle NetCDF as a mesh layer and automatically displays arrow when we give u and v variables in the input NetCDF file.
    – Kazuhito
    Jun 14, 2020 at 0:58
  • @Kazuhito: thank you for your comment. I have u and v-component of velocity as two separate rasters and I have combined them into a single NetCDF. When I load it as a mesh in QGIS, it shows u & v as two separate variables and not as a vector and vector symbology is deactivated. So, I am trying to find: how to combine u and v-components of velocity into a single NetCDF which I can symbolize as a vector in QGIS?
    – Brian
    Jun 14, 2020 at 9:11
  • You already have the needed NetCDF file ( a NetCDF file with u and v variables). Just read the file as mesh.
    – Kazuhito
    Jun 14, 2020 at 9:15
  • that is what I did but QGIS shows u and v as two separate variables and not as a vector. I think i am missing something.
    – Brian
    Jun 14, 2020 at 9:23
  • That's strange. Can you check the file with a NetCDF viewer, such as Panoply?
    – Kazuhito
    Jun 14, 2020 at 9:26

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