To answer your first two questions:
Yes, netcdf4
No, fill value is not set.
And this question:
Simply because I’m not storing strings in it.
I’ve done a few more tests and if I specify the variable sizes explicitly the
resulting file size is small, as I’d expect. So the overhead is coming from not
specifying a fixed variable size.
-Val
> On Apr 5, 2016, at 3:31 PM, dmh@xxxxxxxx wrote:
>
> BTW and out of curiosity, why are you using vlen rather than string?
> =Dennis
>
>
> On 4/5/2016 12:44 PM, Val Schmidt wrote:
>> Hello netcdf folks,
>>
>> I’m testing some python code for writing sets of timestamps and variable
>> length binary blobs to a netcdf file and the resulting file size is
>> perplexing to me.
>>
>> The following segment of python code creates a file with just two variables,
>> “timestamp” and “data”, populates the first entry of the timestamp variable
>> with a float and the corresponding first entry of the data variable with an
>> array of 100 unsigned 8-bit integers. The total amount of data is 108 bytes.
>>
>> But the resulting file is over 73 MB in size. Does anyone know why this
>> might be so large and what I might be doing to cause it?
>>
>> Thanks,
>>
>> Val
>>
>>
>> from netCDF4 import Dataset
>> import numpy
>>
>> f = Dataset('scratch/text3.nc','w')
>>
>> dim = f.createDimension('timestamp_dim',None)
>> data_dim = f.createDimension('data_dim',None)
>>
>> data_t = f.createVLType('u1','variable_data_t’)
>>
>> timestamp = f.createVariable('timestamp','d','timestamp_dim')
>> data = f.createVariable('data',data_t,'data_dim’)
>>
>> timestamp[0] = time.time()
>> data[0] = uint8( numpy.ones(1,100))
>>
>> f.close()
>>
>> ------------------------------------------------------
>> Val Schmidt
>> CCOM/JHC
>> University of New Hampshire
>> Chase Ocean Engineering Lab
>> 24 Colovos Road
>> Durham, NH 03824
>> e: vschmidt [AT] ccom.unh.edu <http://ccom.unh.edu/> <http://ccom.unh.edu
>> <http://ccom.unh.edu/>>
>> m: 614.286.3726
>>
>>
>>
>>
>> _______________________________________________
>> netcdfgroup mailing list
>> netcdfgroup@xxxxxxxxxxxxxxxx <mailto:netcdfgroup@xxxxxxxxxxxxxxxx>
>> For list information or to unsubscribe, visit:
>> http://www.unidata.ucar.edu/mailing_lists/
>> <http://www.unidata.ucar.edu/mailing_lists/>
------------------------------------------------------
Val Schmidt
CCOM/JHC
University of New Hampshire
Chase Ocean Engineering Lab
24 Colovos Road
Durham, NH 03824
e: vschmidt [AT] ccom.unh.edu
m: 614.286.3726
