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NOTICE: This version of the NSF Unidata web site (archive.unidata.ucar.edu) is no longer being updated.
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On Sep 6, 2012, at 7:03 PM, Tom Roche <Tom_Roche@xxxxxxxxx> wrote: > > summary: Suppose you have a netCDF file in the cwd named 'foo.nc' > which has a datavar named 'bar' which contains numeric data ranging > from +1.23e-4 to +5.67e8. I'm looking for executable(s) that supports > use roughly similar to the following commandline input and output: > > $ ncmax ./foo.nc bar > 5.67e8 > > details: > > I'd like to be able to simply, quickly, and automatically test netCDF > data, e.g. to ensure manipulations I'm making don't make unintentional > changes. One obvious way to do this is to check simple statistics, > like the range (max and min) or central tendency (mean or median), of > a datavar, to ensure it changes (or not) as expected. > > I don't particularly care about the technology/API used for the task, > but thought this would be easy to do with NCO, so I tried that first. > After 30 min I still couldn't figure out how, so I punted to google, > where I found > > http://sourceforge.net/projects/nco/forums/forum/9830/topic/4008865 > > which suggests this should be easy to do ... but doesn't say how. > Taking the bait, I examined ncks and ncap2, but, after another 30 min, > was still unenlightened: I can see relatively easily how to create an > output netCDF file, some datavar of which contains the desired value, > but again, that's not what I (and the asker of the above) want--we > just want good old-fashioned stdout. Suggest using the "print" function in ncap2. You still will need an output file, but it can be a dummy file that you ignore. > > So I wrote an R script which demonstrates (albeit crudely) something > like the desired functionality. If you have R and Rscript (with R > packages ncdf4 and fields), you should be able to > > 1 clone https://github.com/TomRoche/GEIA_to_NetCDF to a local folder > > 2 download > > https://github.com/downloads/TomRoche/GEIA_to_netCDF/N2OOC90Y.1A > > to the local folder > > 3 in that folder, run ./GEIA.to.netCDF.r to create ./GEIA_N2O_oceanic.nc > > 4 in that folder, run > > $ Rscript ./netCDF.stats.to.stdout.r 'netcdf.fp="./GEIA_N2O_oceanic.nc"' > 'var.name="emi_n2o"' >> For ./GEIA_N2O_oceanic.nc var=emi_n2o >> cells=64800 >> obs=36143 >> min=5.96e-08 >> max=1.17e+03 >> mean=99.5 >> med=67.7 > > But I strongly suspect there's an easier way--i.e., not involving > writing R--and that someone has scratched this itch before. Am I > missing something? > > TIA, Tom Roche <Tom_Roche@xxxxxxxxx> > > _______________________________________________ > netcdfgroup mailing list > netcdfgroup@xxxxxxxxxxxxxxxx > For list information or to unsubscribe, visit: > http://www.unidata.ucar.edu/mailing_lists/ -- Dr. Christopher Lynnes, NASA/GSFC, Code 610.2, 301-614-5185
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