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Hi Gaby,
I am new to NetCDF format, so please bear with me... When I currently instantiate an array it zeros out all entries, is there a way to avoid that? I don't see anything in the javadocs that allows me to do this. When I write out the array to a file, what I'd like to see in the output file when I invoke ncdump is entries like _, _, _, ... where there is no data.
I guess this must be something to do with fill mode and the value of _FillValue. How are you creating the file? if NetcdfFileWriteable.createNew() or openExisting() what fill mode are you using? With fill mode enabled the array should get pre-filled with whatever '_FillValue' is set to for the variable in question. If you don't want this behavior then set fill mode to false.
according to ncdump man page: ncdump uses ‘_’ to represent data values that are equal to the _FillValue’ attribute for a variable, intended to represent data that has not yet been written. If a variable has no ‘_FillValue’ attribute, the default fill value for the variable type is used if the variable is not of byte type.I would infer from that that if you do want '_' used to represent missing data then you need fill mode enabled. Further the _FillValue used will have to match ncdump's defaults (or be stated explicitly in your netCDF file).
I'm not sure what NJ22 uses as default _FillValues (NaN for floats?, not sure about ints), but it is possible that NJ22's defaults do not match ncdump's expected values (being the C defaults defined in netcdf.h, I assume).
Better practice might be to explicitly define a fill value outside the valid range for your data and add the _FillValue attribute to the variable. That way ncdump should always recognise it whatever value you use.
Hope this helps Simon -- Simon Wood Scientific Programmer (Remote Sensing) National Institute of Water and Atmospheric Research, Wellington, NZ simon.wood@xxxxxxxxxx http://www.niwa.co.nz ============================================================================== To unsubscribe netcdf-java, visit: http://www.unidata.ucar.edu/mailing-list-delete-form.html ==============================================================================
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