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use of unstructured grid

Added by Ed Hawkins over 13 years ago

I am trying to regrid some data from a regular lat-lon grid onto a unstructured grid - specifically the example in the documentation:

https://code.zmaw.de/embedded/cdo/1.5.2/cdo.html#x1-803000A.2

using

cdo -remapcon2,gridhex.cdo in.nc out.nc

where gridhex.cdo is the example given, but this gives the error:

Warning (gridFromFile) : Invalid grid name : unstructured

I am using cdo version 1.4.5. Is this type of transformation possible? Or am I doing something wrong?

Thanks,
Ed Hawkins


Replies (3)

RE: use of unstructured grid - Added by Uwe Schulzweida over 13 years ago

The name of this grid type was changed from cell to unstructured in CDO version 1.5.1. To use the example with CDO version 1.4.5 you have to change the first line to:

gridtype  = cell
Please note that this is only a very simple example of an unstructured grid. For this reason the 10 pentagons in the pictures are not described.

Best regards,
Uwe

RE: use of unstructured grid - Added by Ed Hawkins over 13 years ago

Thanks Uwe - that example now works.

If I wanted an icosahedral grid with hexagaons and pentagons, is it possible to define a .cdo file with two types of polygon?

Or could you use all 'hexagons' and define two of the vertices to be coincident for the pentagons?

Regards,
Ed.

RE: use of unstructured grid - Added by Uwe Schulzweida over 13 years ago

Hi Ed,

Yes, you can define only one polygon type. The pentagons have to be defined as hexagons and the sixth vertex is the same as the fifth (or first) vertex. We use it also in this way in our icosahedral model ICON.

Best regards,
Uwe

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