CDO

hey!

Try this one

cdo -setattribute,heff@coordinates="lat_scaler lon_scaler",kmt@coordinates="lat_scaler lon_scaler",dxt@coordinates="lat_scaler lon_scaler",dyt@coordinates="lat_scaler lon_scaler" GIOMAS_heff_1979.nc t.nc 

you file is not CF-conform. so CDO as problems with linking data and grid. Probably you need to fix the missing values, too.

possibly something like this

cdo -setattribute,heff@coordinates="lat_scaler lon_scaler",kmt@coordinates="lat_scaler lon_scaler",dxt@coordinates="lat_scaler lon_scaler",dyt@coordinates="lat_scaler lon_scaler,heff@missing_value=9999.9,kmt@missing_value=0" GIOMAS_heff_1979.nc t_fixMissing.nc

hth
ralf

Hi Ralf,

Thank you very much for a prompt reply! The solution worked like a charm!
The only tweaks I need to make was set coordinates in the same manner for two other variables (z and dz) which were throwing an error when I tried to regrid the "t_fixMissing.nc" file.

Thanks again!

Regards,
Shreya

Shreya Trivedi wrote in RE: Remap Error: Generic Coordinates not supported:

Hi Ralf,

Thank you very much for a prompt reply! The solution worked like a charm!
The only tweaks I need to make was set coordinates in the same manner for two other variables (z and dz) which were throwing an error when I tried to regrid the "t_fixMissing.nc" file.

Thanks again!

Regards,
Shreya

those are pure vertical axes without any horizontal grid. for regridding just select the horizontal fields and do the remapping afterwards:

cdo -remapbil,global_1 -selname,heff,kmt t_fixMissing.nc t_remapped.nc

Thanks a tonne, Ralf, for a detailed solution and an explanation!
It works perfectly now!

Best,
Shreya

Hi Shreya and Ralf,

I meet the same problem when I regrid the Arctic sea ice data from PIOMAS. Since PIOMAS do not provide 'nc' file, I convert the 'hiday.1979' to 'PIOMAS1979.nc' first. I failed to regrid this data, so I tried to add the coordinates and missing_value following the suggestion by Ralf:

cdo -setattribute,sithick@coordinates="clat clon",sithick@missing_value=9999.9 PIOMAS1979.nc t.nc

Then I regrid 't.nc' on the grid 'outgrid1.txt', but I still got the problem:

cdo remapbil,outgrid1.txt -selname,sithick t.nc output.nc
cdo(1) selname: Process started
Warning (cdfInqContents): Coordinates variable clat can't be assigned!
Warning (cdfInqContents): Coordinates variable clon can't be assigned!

cdo    remapbil (Abort): Unsupported generic coordinates (Variable: sithick)!
terminate called without an active exception
Aborted (core dumped)

I am attaching the files for your kind perusal.
Could you please help my with this problem? Many thanks in advance for any help!

Hi Yijun,

I have faced a lot of problems before dealing with the GIOMAS dataset. It's slightly tricky to work with. I looked at your files and tried to work around the same way as I did with my files. However, I am afraid I am still getting the same errors. I thought it will be better if you could have a look at what I exactly did to my dataset to make it work. Hence, sharing my "ncdump -h" with you:

1. cdo -setreftime,1850-01-01,00:00:00,1day -settaxis,1979-01-01,00:00:00,1month -setcalendar,proleptic_gregorian GIOMAS.heff.H1979-2014.nc GIOMAS.heff.H1979-2014_TRF.nc
#Set the reference time.

2. cdo -setattribute,heff@coordinates=lat_scaler lon_scaler,kmt@coordinates=lat_scaler lon_scaler,dxt@coordinates=lat_scaler lon_scaler,z@coordinates=lat_scaler lon_scaler,dz@coordinates=lat_scaler
lon_scaler,dyt@coordinates=lat_scaler lon_scaler,heff@missing_value=9999.9,kmt@missing_value=0 GIOMAS_heff_1979-2014_TRF.nc t_fixMissing.nc
#Set missing values and add attributes to all the variables except pure vertical axes.

3. cdo remapbil,Griddes.txt t_fixMissing.nc GIOMAS_heff_1979-2014_Regridded.nc #Finally, a bilinear interpolation method for regridding based on the desired grid description

See if this helps? If not then I am sure CDO community (Ralf in my case) was super helpful and they will address your query promptly!

Shreya

Shreya Trivedi wrote in RE: Remap Error: Generic Coordinates not supported:

Hi Yijun,

I have faced a lot of problems before dealing with the GIOMAS dataset. It's slightly tricky to work with. I looked at your files and tried to work around the same way as I did with my files. However, I am afraid I am still getting the same errors. I thought it will be better if you could have a look at what I exactly did to my dataset to make it work. Hence, sharing my "ncdump -h" with you:

cdo -setreftime,1850-01-01,00:00:00,1day -settaxis,1979-01-01,00:00:00,1month -setcalendar,proleptic_gregorian GIOMAS.heff.H1979-2014.nc GIOMAS.heff.H1979-2014_TRF.nc

#Set the reference time.

cdo -setattribute,heff@coordinates=lat_scaler lon_scaler,kmt@coordinates=lat_scaler lon_scaler,dxt@coordinates=lat_scaler lon_scaler,z@coordinates=lat_scaler lon_scaler,dz@coordinates=lat_scaler 
    lon_scaler,dyt@coordinates=lat_scaler lon_scaler,heff@missing_value=9999.9,kmt@missing_value=0 GIOMAS_heff_1979-2014_TRF.nc t_fixMissing.nc

#Set missing values and add attributes to all the variables except pure vertical axes.

cdo remapbil,Griddes.txt t_fixMissing.nc GIOMAS_heff_1979-2014_Regridded.nc #Finally, a bilinear interpolation method for regridding based on the desired grid description

See if this helps? If not then I am sure CDO community (Ralf in my case) was super helpful and they will address your query promptly!

Shreya

Shreya Trivedi wrote in RE: Remap Error: Generic Coordinates not supported:

Shreya Trivedi wrote in RE: Remap Error: Generic Coordinates not supported:

Hi Yijun,

I have faced a lot of problems before dealing with the GIOMAS dataset. It's slightly tricky to work with. I looked at your files and tried to work around the same way as I did with my files. However, I am afraid I am still getting the same errors. I thought it will be better if you could have a look at what I exactly did to my dataset to make it work. Hence, sharing my "ncdump -h" with you:

[...]

#Set the reference time.

[...]

#Set missing values and add attributes to all the variables except pure vertical axes.

[...]

See if this helps? If not then I am sure CDO community (Ralf in my case) was super helpful and they will address your query promptly!

Shreya

Hi Yijun,

the PIOMAS file does not have any attribute for the coordinate variables time, lat, lon.

ncdump -h PIOMAS1979.nc

netcdf PIOMAS1979 {
dimensions:
    x = 360 ;
    y = 120 ;
    t = 365 ;
variables:
    double clat(y, x) ;
    double clon(y, x) ;
    double time(t) ;
    double sithick(t, y, x) ;
}

You have to add these before you can remap the data.

ncatted -O -a units,clat,c,c,'degrees_north' \
           -a units,clon,c,c,'degrees_east' \
           -a coordinates,sithick,c,c,'clat clon' \
           PIOMAS1979.nc tmp.nc

Set the time like Shreya has described.

cdo -setreftime,1850-01-01,00:00:00,1day \
    -settaxis,1979-01-01,00:00:00,1month \
    -setcalendar,proleptic_gregorian \
    -selvar,sithick tmp.nc piomas1979_with_attributes.nc

Then you can remap the data.

cdo remapbil,outgrid1.txt piomas1979_with_attributes.nc outfile.nc

Hi Shreya and Karin

Thank you all so much for the prompt reply and detailed solution! The detailed process shared by Shreya helps me a lot and the solution from Karin works perfectly and completely solves my problem!

Thanks again for your help!

All the best,
Yijun

Hello All,
I am also facing same problem "cdo remapbil (Abort): Unsupported generic coordinates (Variable: BC)!".
I tried to fix it with following commands as per forum suggestions-
1.cdo setattribute,BC@coordinates="lat_scaler lon_scaler" LE_Indore_BC_replace.nc LE_Indore_BC_remap1.nc
2. ncatted -a grid_mapping,BC,d,, LE_Indore_BC_replace.nc
But I got error "Warning (cdfScanVarAttr): NetCDF: Variable not found - >lat_scaler<"

Then used again solution from forum
"ncatted -O -a coordinates,BC,d,, LE_Indore_BC_remap1.nc".
But now again getting the same error "cdo remapbil (Abort): Unsupported generic coordinates (Variable: BC)!"

Ncdump of my original file is as below and I would like to remap 1km grid to 10km
.
ncdump -h LE_Indore_BC_replace.nc
netcdf LE_Indore_BC_replace {
dimensions:
lon = 214 ;
lat = 164 ;
variables:
double lon(lon) ;
lon:standard_name = "projection_x_coordinate" ;
lon:units = "m" ;
lon:axis = "X" ;
double lat(lat) ;
lat:standard_name = "projection_y_coordinate" ;
lat:units = "m" ;
lat:axis = "Y" ;
char crs ;
crs:grid_mapping_name = "latitude_longitude" ;
crs:long_name = "CRS definition" ;
crs:longitude_of_prime_meridian = 0. ;
crs:semi_major_axis = 6378137. ;
crs:inverse_flattening = 298.257223563 ;
crs:spatial_ref = "GEOGCS[\"unknown\",DATUM[\"WGS_1984\",SPHEROID[\"WGS 84\",6378137,298.257223563,AUTHORITY[\"EPSG\",\"7030\"]],AUTHORITY[\"EPSG\",\"6326\"]],PRIMEM[\"Greenwich\",0,AUTHORITY[\"EPSG\",\"8901\"]],UNIT[\"degree\",0.0174532925199433,AUTHORITY[\"EPSG\",\"9122\"]],AXIS[\"Longitude\",EAST],AXIS[\"Latitude\",NORTH]]" ;
crs:crs_wkt = "GEOGCS[\"unknown\",DATUM[\"WGS_1984\",SPHEROID[\"WGS 84\",6378137,298.257223563,AUTHORITY[\"EPSG\",\"7030\"]],AUTHORITY[\"EPSG\",\"6326\"]],PRIMEM[\"Greenwich\",0,AUTHORITY[\"EPSG\",\"8901\"]],UNIT[\"degree\",0.0174532925199433,AUTHORITY[\"EPSG\",\"9122\"]],AXIS[\"Longitude\",EAST],AXIS[\"Latitude\",NORTH]]" ;
crs:GeoTransform = "75.11883988975056 0.009469308696612446 0 23.80153487113431 0 -0.009469308696612446 " ;
float BC ;
BC:_FillValue = NaNf ;
BC:missing_value = NaNf ;
BC:coordinates = "lon lat"

Can any one help to resolve issue this issue.

Best,
Suvarna

Hi Survana,

without the file I can only say that the grid_mapping attribute of BC is missing. Try

cdo -setattribute,BC@grid_mapping=crs infile outfile

Hi Karin,
Thank you.
After doing this I have used below command.
cdo remapbil,CAMS_Indore_NMVOC.nc ifile.nc ofile.nc

It is giving error
"Warning (cdfScanVarAttr): NetCDF: Variable not found - crs
cdo remapbil (Abort): Unsupported generic coordinates (Variable: BC)!". File is attached.

Best,
Suvarna

There is not enough information about the grid mapping and I was not able to write a correct grid description file. You should have more information about the grid or projection of the data.

Hi Karin,

Projection of file is WGS1984 GCS. Original file was shapefile with WGS1984 UTM projection.Then using python, I convert it to ncfile and then following command has been used to regrid it in GCS projection.

gdalwarp -r bilinear -t_srs "+proj=lonlat +datum=WGS84 +no_defs" NETCDF:"ifile.nc":BC_Emissio ofile.nc.

Best,
Suvarna

If the grid is part of India I guess it is realley simple because only the units are wrong. Instead of meters it has to be degrees.

ncatted -O -a units,lon,o,c,"degrees_east" -a units,lat,o,c,"degrees_north" LE_Indore_BC_replace.nc LE_Indore_BC_replace_degrees.nc

Yes. Thanks a lot. It's works.

Good to hear. It is always important to take care of the correct units when doing conversions or calculations.