Hi,
Many thanks to Russ and David Pierce for the tips.
With ncgen I generated a netcdf-4 classic and
a netcdf-4 file by using the command line options
-k "netCDF-4 classic model" and -k "netCDF-4",
respectively.
The nc files generated this way have the expected format:
$ ncdump -k sample4.nc
netCDF-4
$ ncdump -k sample4-classic.nc
netCDF-4 classic model
and differ in length by 13 bytes:
$ ls -l sample4*nc
-rw-r--r-- 1 gabriel users 15695 Dec 21 17:29 sample4-classic.nc
-rw-r--r-- 1 gabriel users 15708 Dec 21 16:44 sample4.nc
which is exactly the length of the string "classic model". So I
checked if the difference in the files comes only from meta-data
$ od -c sample4.nc | more
0000000 211 H D F \r \n 032 \n 002 \b \b \0 \0 \0 \0 \0
0000020 \0 \0 \0 \0 377 377 377 377 377 377 377 377 \ = \0 \0
0000040 \0 \0 \0 \0 0 \0 \0 \0 \0 \0 \0 \0 332 323 H *
...
$ od -c sample4-classic.nc | more
0000000 211 H D F \r \n 032 \n 002 \b \b \0 \0 \0 \0 \0
0000020 \0 \0 \0 \0 377 377 377 377 377 377 377 377 O = \0 \0
0000040 \0 \0 \0 \0 0 \0 \0 \0 \0 \0 \0 \0 I 263 j }
...
The dump seems to indicate that the data in netCDF-4 is
different from that in neCDF-4 classic, even though I have
not used any "new" API features (these files are obtained from
a cdl file with ncgen). Or am I interpreting incorrectly the output
from "od" ?
Thank you.
Gabriel
Russ Rew wrote:
Hi Gabriel,
I have installed netCDF-4.0.1 and I generated
a .nc file using ncgen.
I would like to ask what is the flavor of the
format generated by ncgen: is it the so-called
netcdf4-classic or the new new hdf5-based
format?
How can I check the which flavor is generated
by ncgen?
You can use the "-k" option of ncdump to determine what kind of netCDF
file you have. For example:
$ ncdump -k foo.nc
classic
Similarly, you can use the "-k" option of ncgen to specify which kind of
netCDF file to generate (or to generate code for).
--Russ
