mask out a netcdf database using a landuse database
Added by Natalia L over 5 years ago
Hello,
I have a netcdf file with a variable v(lat,lon,v), and I have the land cover corine database which I have already converted to a netcdf file with the same grid dimensions to the netcdf with the variable v.
So, I want to remap my netcdf file with the variable based on the land uses of corine database. For example, I want to keep only land (i.e. excluding the water surfaces) etc.
Could anyone help me on how I can do that?
Thanks a lot in advance
Regards,
Natalia
Replies (3)
RE: mask out a netcdf database using a landuse database - Added by Karin Meier-Fleischer over 5 years ago
Hi Natalia,
without your data I can only guess.
Assume:
your_data.nc: your data file
corine_data.nc: your corine file used to be the mased input on same grid as your_data_nc
mask_land_only.nc: is the newly created masked file land only
your_data_masked.nc: shows only your data on land
Create land-sea mask from corine_data.nc:
cdo -setrtomiss,-20000,0 corine_data.nc mask_land_only.nc
Mask your_data with mask_land_only to get the values of your_data.nc only over land:
cdo ifthen mask_land_only your_data.nc your_data_masked.nc
-Karin
RE: mask out a netcdf database using a landuse database - Added by Natalia L over 5 years ago
Thank you very much!
regards,
Natalia
RE: mask out a netcdf database using a landuse database - Added by Natalia L over 5 years ago
Hi again,
the land use database I use has the id 20 for waters . So, I finally I masked my data as following
cdo setctomiss,20 $Database_outdir/land_use_map.nc $Database_outdir/land_use_map_only_land.nc"
cdo ifthen $Database_outdir/land_use_map_only_land.nc $Database_outdir/input.nc $Database_outdir/output.nc
The masking is done correctly however all the no land cells are filled in with Nan values. Does this mean that something is wrong ? How I could make the masking and no land cells values be zero instead of Nan?
thanks
N