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Hello, I have an 'understanding' type of question. I have omitted details of my OS, NetCDF installation, and a minimal example since I do not think they are important for my question, but I can provide these details if they are important. When I attempt to open a MERRA file using the NetCDF C++ libraries, with a line like the following, in my code: NcFile datafile(" http://goldsmr2.sci.gsfc.nasa.gov/opendap/hyrax/MERRA/MAT1NXSLV.5.2.0/1990/01/MERRA100.prod.assim.tavg1_2d_slv_Nx.19900101.hdf?U50M_EOSGRID_Data_Fields[0:23][282:282][441:441] ",NcFile::read); ...I notice that quite a lot (nearly 20 MB) is being transferred from Hyrax to my PC. However, all that I am interested in are the actual array values (24 separate 32-bit real numbers) of the U50M_EOSGRID_Data_Fields. It has been suggested that the entire array (of size 24*361*540 32-bit reals) is being transferred by NetCDF before any subsetting takes place, is this true? If so, is it then not possible to use OPeNDAP URLs to subset on-the-fly through the NetCDF libraries? Thank you for your help! Taylor
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