CDO time step writing - missing grid information
Added by Sarah Roffe over 2 years ago
Good day,
I tried to add in a time step for my netcdf file (attached - this file was created on R by merging daily tiff timestep files for CHIRPS). I used this code:
cdo settaxis,1981-01-01,12:00:00,1day Chirps_1981.nc Chirps_1981_dates.nc
And received this error:
Warning (cdf_read_mapping_atts): Text attribute crs:grid_mapping_name missing!
setBaseTime : Unsupported TIMEUNIT: unknown!
Can anyone assist with how to write the missing grid information using CDO?
Kind regards,
Sarah
| Chirps_1981.nc (45 MB) Chirps_1981.nc |
Replies (1)
RE: CDO time step writing - missing grid information - Added by Karin Meier-Fleischer over 2 years ago
Hi Sarah,
your data file is not CF-conform, the time dimension is named z and have no units and calendar attribute. Furthermore, the crs variable doesn't have the grid_mapping_name attribute which is needed.
1. Rename time variable and dimension z to time.
ncrename -O -v z,time -d z,time Chirps_1981.nc tmp0.nc
2. Add missing attributes
ncatted -O \
-a grid_mapping_name,crs,c,c,'latitude_longitude' \
-a standard_name,time,c,c,'time' \
-a long_name,time,o,c,'time' \
-a units,time,o,c,'days since 1981-1-1 12:00:00' \
-a calendar,time,c,c,'proleptic_gregorian', \
-a axis,time,c,c,'T' \
tmp0.nc tmp1.nc
3. Set time axis and missing value
cdo -r -setctomiss,-9999.0 \
-settaxis,1981-01-01,12:00:00,1day \
-setreftime,1981-01-01,12:00:00,1day \
tmp1.nc Chirps_1981_dates.nc
-Karin