[GRASS-dev] question about gdal

[Michael Barton]

This is a question for any gdal experts out there. 

I'm working with reading NetCDF files. gdal does an admirable job of this. Many of the NetCDF climate data files have many bands and I'd like import only some of them. Specifying a particular NetCDF SUBSET will allow gdal to read the data for a particular variable.

For example, ...

gdal_translate NETCDF:"/Users/cmbarton/Dropbox/NCAR_files/ppt_A1.SRESA1B_EA1-8.CCSM.atmm.2000-01_cat_2099-12.nc":ppt /Users/cmbarton/Dropbox/NCAR_files/out.tif 

...will translate all of the data sets for the ppt (precipitation) variable

AFAICT, the -mo flag in gdal_translates also allows it to operate on a subset of data specified by a metadata option. But I can't figure out the proper syntax to use it. There are hints in <http://www.gdal.org/frmt_netcdf.html>, but the exact way to specify relevant metadata still eludes me. It seems like to translate only the bands for which the time variable = 730015.5 days after 1-01-01, I need to run...

gdal_translate -mo ppt#NETCDF_DIMENSION_time=730015.5 NETCDF:"/Users/cmbarton/Dropbox/NCAR_files/ppt_A1.SRESA1B_EA1-8.CCSM.atmm.2000-01_cat_2099-12.nc":ppt /Users/cmbarton/Dropbox/NCAR_files/out.tif

But this ignores the -mo specification and simply translates all bands.

So does anyone know how to specify the metadata for time in this case?

Thanks
Michael

_____________________
C. Michael Barton
Visiting Scientist, Integrated Science Program
National Center for Atmospheric Research &
University Consortium for Atmospheric Research
303-497-2889 (voice)

Director, Center for Social Dynamics & Complexity 
Professor of Anthropology, School of Human Evolution & Social Change
Arizona State University
www: http://www.public.asu.edu/~cmbarton, http://csdc.asu.edu





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