Hi,
An undocumented feature of ncgen in netCDF-2 was that null padding was
added to strings that were shorter than the last dimension of a
multidimensional character variable, instead of just concatenating them.
This permitted using strings of different lengths in an array in CDL,
for example:
netcdf bug {
dimensions:
scan = 4 ;
string_len = 10 ;
variables:
char name(scan, string_len) ;
data:
name
"Methane",
"Ammonia",
"Water",
"Acetylene" ;
}
In versions 3.3 and 3.3.1, unfortunately this feature no longer works.
Instead the strings are just concatenated, as they would be with a
1-dimensional variable. For example, when the above CDL file is
converted to a netCDF file using the "-b" option to ncgen, running
ncdump on the result produces:
netcdf bug {
dimensions:
scan = 4 ;
string_len = 10 ;
variables:
char name(scan, string_len) ;
data:
name
"MethaneAmm",
"oniaWaterA",
"cetylene",
"" ;
}
A patch is now available that fixes the problem, from
http://www.unidata.ucar.edu/packages/netcdf/patch-3.3.1-2
The problem description and a link to the patch have been added to the
"Known Problems" page for netCDF at
http://www.unidata.ucar.edu/packages/netcdf/known_problems.html
The fix will be included in the next minor release.
--Russ
_____________________________________________________________________
Russ Rew UCAR Unidata Program
russ@xxxxxxxxxxxxxxxx http://www.unidata.ucar.edu
