Merging grids
Added by Francis Rayder almost 11 years ago
I know that it is possible to split a dataset into different coordinate regions. For example, with
cdo sellonlatbox,180,-180,90,66 input.nc output.nc
I got only the northermost latitudes from a dataset, and with
cdo sellonlatbox,180,-180,66,33 input.nc output.nc
I got the latitudes further south, and so on. Now, my question is, is it possible to combine these split fields again? After I modify them indivually, I would like to put them back together again. I tried merge, but that only works for fields with different variables.
Replies (3)
RE: Merging grids - Added by Ralf Mueller almost 11 years ago
have you tested mergegrid?
The other option is the scatter-gather
combination. I wanted to write an operator news feed for a long time, but didn't manage to do, yet. anyhow, the short answer is
scatter,n,m
split regular fields inn x m
parts andgather
is putting it all together again
here comes a litte example using the internal topography operator 'topo'
cdo -f nc -topo topo.nc
- split in to 3x2 part with
cdo -f nc scatter,3,2 topo.nc topo_scat
- results:
-rw-rw-r-- 1 ram users 173K Nov 13 15:52 topo_scat00005.nc -rw-rw-r-- 1 ram users 173K Nov 13 15:52 topo_scat00004.nc -rw-rw-r-- 1 ram users 173K Nov 13 15:52 topo_scat00003.nc -rw-rw-r-- 1 ram users 173K Nov 13 15:52 topo_scat00002.nc -rw-rw-r-- 1 ram users 173K Nov 13 15:52 topo_scat00001.nc -rw-rw-r-- 1 ram users 173K Nov 13 15:52 topo_scat00000.nc
- now use cdo plotting operators
for file in topo_scat*nc; do cdo shaded,device=png -chname,topo,$file $file plot_$file; done
with output-rw-rw-r-- 1 ram users 87K Nov 13 15:53 plot_topo_scat00000.nc_topo_scat00000.nc.png -rw-rw-r-- 1 ram users 94K Nov 13 15:53 plot_topo_scat00001.nc_topo_scat00001.nc.png -rw-rw-r-- 1 ram users 94K Nov 13 15:53 plot_topo_scat00002.nc_topo_scat00002.nc.png -rw-rw-r-- 1 ram users 88K Nov 13 15:53 plot_topo_scat00003.nc_topo_scat00003.nc.png -rw-rw-r-- 1 ram users 98K Nov 13 15:53 plot_topo_scat00004.nc_topo_scat00004.nc.png -rw-rw-r-- 1 ram users 88K Nov 13 15:53 plot_topo_scat00005.nc_topo_scat00005.nc.png
- check files with you favourite image viewer
should look like this:
all_small.png (205 KB) all_small.png | |||
all.png (345 KB) all.png |
RE: Merging grids - Added by Francis Rayder almost 11 years ago
Thank you, mergegrid worked. Because that command is not documented in the pdf I have, I was not aware it existed.
RE: Merging grids - Added by Ralf Mueller almost 11 years ago
The html and pdf links at the wiki should always represent the latest documentation.