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[netCDF #AJO-721072]: Re: [netcdfgroup] netCDF software for analysing NCAR reanalysis atlas

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  • Subject: [netCDF #AJO-721072]: Re: [netcdfgroup] netCDF software for analysing NCAR reanalysis atlas
  • Date: Mon, 22 Mar 2010 13:39:48 -0600
Jakub,

> >> I am beginner to netCDF and looking for netCDF software to analyse
> >> NCEP/ NCAR reanalysis data such as
> >> ftp://ftp.cdc.noaa.gov/Datasets/ncep.reanalysis.dailyavgs/pressure/hgt.2010.nc
> >> for scientific project of weather forecasting. I am looking for
> >> software that convert selected data to text - for example hgt data on
> >> level 850, lat 50 to 52, lon 30 to 33 and any time. nc2text have this
> >> functionality, but I can use it to retrieve 4-dimentions data. What
> >> software do you reccomend to do it?
> >
> > We have recently added an answer to this question to our Frequently
> > Asked Questions list
> >
> >  How do I convert netCDF data to ASCII or text?
> >  http://www.unidata.ucar.edu/netcdf/docs/faq.html#converttotext
> >
> > referencing various ways to get a text view of netCDF data.  Please let
> > us know if this still doesn't answer your question.
> >
> > --Russ
> >
> >
> 
> Thank you for your answer, but I would expect more detailed information. I
> know where I can find a list of software, but I can't find software that can
> choose data from 4-dimensional hgt variable of file like
> ftp://ftp.cdc.noaa.gov/Datasets/ncep.reanalysis.dailyavgs/pressure/hgt.2010.nc
>  I
> don't need to convert all file because I get on output about 0,5 GB file
> with aa list of every value. I would like to choose hgt values on chosen
> latitude, longitude, level and time variable values. For example value of
> hgt variable on 3 March to 6 April, on level 850, on latitude 50 to 60 and
> longitude 20 to 40.
> 
> I expect short aswer with name of netCDF software that can do it.

If the data is available from a TDS (THREDDS Data Server) instead of an FTP
server, you can use the "netCDF subset service" to get an ASCII dump of data 
within a lat/lon bounding box.  The netCDF subset service is described here:

  
http://www.unidata.ucar.edu/projects/THREDDS/tech/interfaceSpec/NetcdfSubsetService.html

and examples of it are here:

  
http://motherlode.ucar.edu:8080/thredds/ncss/grid/fmrc/NCEP/NAM/CONUS_80km/NCEP-NAM-CONUS_80km_best.ncd/dataset.html
  http://michigan.glin.net/thredds/ncss/grid/bathy/crm_great_lakes/dataset.html

For a local file, use a higher level package that makes use of the netCDF 
library
for data access, such as Ferret, NCL, NCO, or CDO.  For example, NCO has a 
utility
named ncks that can extract and print variable values, given a bounding box in
coordinate space:

  http://nco.sourceforge.net/nco.html#ncks-netCDF-Kitchen-Sink

--Russ

Russ Rew                                         UCAR Unidata Program
address@hidden                      http://www.unidata.ucar.edu



Ticket Details
===================
Ticket ID: AJO-721072
Department: Support netCDF
Priority: Normal
Status: Closed