nc4 compression control
Added by Marston Ward over 11 years ago
Hi,
I'm trying to create nc4 files from a grub conversion and I want to maximize the compression. What is the default compression and how do I modify that?
Appreciate your help,
/M
Replies (3)
RE: nc4 compression control - Added by Marston Ward over 11 years ago
The above question should say grib, not grub. Damn autocorrect!
RE: nc4 compression control - Added by Etienne Tourigny over 11 years ago
Hi,
My personal experience is that a deflate level of 6 is probably ok if you want to minimize size, with 2 it's much faster with only a 10% size penalty, and with 9 it's not really worth the (much longer) processing time.
Using the latest cdo version, do something like:
cdo -f nc4c -z zip_9 in.grib out.nc
from cdo -h:
-z szip SZIP compression of GRIB1 records
jpeg JPEG compression of GRIB2 records
zip[_1-9] Deflate compression of netCDF4 variables