pangeo-data / xESMF

Universal Regridder for Geospatial Data
http://xesmf.readthedocs.io/
MIT License
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Regrid from icosahedral (triangular) grid to rectangular #367

Open albertotb opened 2 weeks ago

albertotb commented 2 weeks ago

Is this package able to regrid from a triangular grid to a rectangular one? As an use case the data from this model https://www.dwd.de/EN/ourservices/nwp_forecast_data/nwp_forecast_data.html is distributed as a triangular grid. They provide instructions to transform it into a rectangular grid using CDO (https://www.dwd.de/DE/leistungen/opendata/help/modelle/Opendata_cdo_EN.pdf?__blob=publicationFile&v=3), but I was curious if this package could provide an alternative.

huard commented 2 weeks ago

xESMF supports unstructured grids, so I suspect it should indeed be possible.

See https://xesmf.readthedocs.io/en/latest/notebooks/Using_LocStream.html

albertotb commented 2 weeks ago

Thanks, I will take a look!. If you are looking for examples for the documentation the data for that particular model is distributed openly. In any case feel free to close the issue whenever.

aulemahal commented 2 weeks ago

@huard I don't think a LocStream is an unstructrued grid, it rather is a list of points, i.e. there is no relation between each point. ESMF supports this with its MeshGrid, but the implementation is not yet available though xESMF because there is no standard / data structure in the xarray world that supports those. Or at least, not that we were aware of when we last looked.

ESMpy however, is capable of doing it. @albertotb I would suggest you take a look there :https://earthsystemmodeling.org/esmpy_doc/release/latest/html/index.html It will be quite more complicated than with all the xESMF goodies, but at least you'll stay in python...

huard commented 2 weeks ago

You're right, sorry about the misdirection.