"Warning (cdf_read_xcoord): Unsupported array structure" prolem

Dear CDO community:

I want to convert some data defined at unstructured grids to the regular lat-lon grid 
          using CDO (remapdis for this case). For some reasons, the 1d and 2d unstructured data have 
          to be written as separate files (1d.nc 2d.nc as attached). For 1d.nc, I use the following command
          and this successfully converted the data:

ncks -v phis,ps,lon_nv,lat_nv 1d.nc tmp.nc
           cdo remapdis,n32 tmp.nc 1d-ll.nc
           rm -rf tmp.nc

For 2d.nc, I first selected variables from 1d.nc and 2d.nc, respectively. Then I combined them to a sinlge file. 
           These are done via NCO's ncks. Then when cdo remapdis is invoked, it aborts with "Warning (cdf_read_xcoord): Unsupported array structure".
           The detailed commands are as follows:

ncks -v temperature 2d.nc tmp-2d.nc
           ncks -v lon_nv,lat_nv,nlev 1d.nc tmp-1d.nc
           ncks tmp-1d.nc tmp-2d.nc
           cdo remapdis,n32 tmp-2d.nc 2d-ll.nc
           rm -rf tmp-1d.nc tmp-2d.nc

Could anyone help me with this problem? Thanks in advance!

Best
Yi

Download all files

1d.nc (342 KB) 1d.nc	one dimensional data array
2d.nc (7.03 MB) 2d.nc	two dimensional data array

Replies (5)

RE: "Warning (cdf_read_xcoord): Unsupported array structure" prolem - Added by Ralf Mueller about 6 years ago

I merged your files manually with ncdump/ncgen - not so smart, but it worked.

cdo rempapdis worked

% cdo -P 8 remapdis,global_1 2dx.nc 2dx_1DegGlobal.nc          
Warning (cdf_read_xcoord): Unsupported array structure, skipped variable avor!
Warning (cdf_read_xcoord): Unsupported array structure, skipped variable rvor!
cdo remapdis: Distance-weighted average weights from unstructured (2562) to lonlat (360x180) grid
cdo remapdis: Distance-weighted average weights from unstructured (7680) to lonlat (360x180) grid
cdo remapdis: Processed 627324 values from 7 variables over 1 timestep [2.14s 65MB]

There must be an NCO command to merge both files, but I couldnt find it, sry

hth
ralf

Download all files

2dx.nc (7.37 MB) 2dx.nc
2dx_1DegGlobal.zip (23 MB) 2dx_1DegGlobal.zip

RE: "Warning (cdf_read_xcoord): Unsupported array structure" prolem - Added by Yi Zhang about 6 years ago

Dear Ralf:

Thanks a lot!
I have tried your suggestion and it worked (though two variables are missing),
while this strategy may be kind of slow when the data become larger.

I do find this problem is sensitive to the way how one merges the data.
For example, if I use "ncks 1d.nc 2d.nc" to append one file to another.
then "cdo remapdis" is able to convert those 1d data but not those 2d data:

Warning (cdf_read_xcoord): Unsupported array structure, skipped variable temperature!
Warning (cdf_read_xcoord): Unsupported array structure, skipped variable avor!
Warning (cdf_read_xcoord): Unsupported array structure, skipped variable rvor!
Warning (cdf_read_xcoord): Unsupported array structure, skipped variable geopotential!
Warning (cdf_read_xcoord): Unsupported array structure, skipped variable u_edge!
Warning (cdf_read_xcoord): Unsupported array structure, skipped variable v_edge!
cdo remapdis: Distance-weighted average weights from unstructured (7680) to gaussian (128x64) grid
cdo remapdis: Distance-weighted average weights from unstructured (2562) to gaussian (128x64) grid

While if I use "cdo merge 1d.nc 2d.nc 12d.nc",
"cdo remapdis,n32" gives

cdo remapdis (Abort): Unsupported generic coordinates (Variable: lon_nt)!

--
Best
Yi

RE: "Warning (cdf_read_xcoord): Unsupported array structure" prolem - Added by Ralf Mueller about 6 years ago

cdo merge does not work for your purpose - that's why I didnt suggest it ;-)

RE: "Warning (cdf_read_xcoord): Unsupported array structure" prolem - Added by Yi Zhang about 6 years ago

Just for an update.
I found that if I use "ncks 2d.nc 1d.nc" that appends 2d data to 1d data, it will give the same result as using "ncdump/ncgen";

For the missing two variables, if I write an additional 1d data array (defined at location_nt dim) to the 1d.nc,
then merge the data as above, "cdo remapdis" will remap all data correctly.
The original 1d.nc does not have a variable defined at location_nt dim, which may cause this problem.

Thanks.

RE: "Warning (cdf_read_xcoord): Unsupported array structure" prolem - Added by Ralf Mueller about 6 years ago

thx for sharing your solution ;-)

cheers
ralf

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