Re: [netcdfgroup] Extracting data from NetCDF

You should probably do this with one of the Netcdf tool applications.

http://www.unidata.ucar.edu/software/netcdf/docs/netcdf-tutorial.html#Tools
http://www.unidata.ucar.edu/software/netcdf/software.html

If you do not need the ascii output formatted into columns, then you can extract the desired subset into a separate Netcdf file with one NCO command. Then use ncdump to print that file as ascii CSV.
NCL can read Netcdf, get the desired subset, and output formatted 
ascii with only a few script commands.  There is a learning curve 
for the script language.
There are plenty of other alternatives.  Perhaps you should take 
inventory of which Netcdf tools are already on your computer system.
You can also use the Netcdf API interfaces directly from C, Fortran, 
and Java, if that seems better for what you want to do.  See the 
Netcdf tutorial for more details.  In particular, the examples for 
"pres_temp_4D" show how to read a Netcdf variable of the same 
dimensionality as your data.  You then just subscript as needed, and 
add formatted write commands.
Also, if you are just reading the ascii result into another software 
package, check the documentation and available extensions carefully 
before putting your energy into making an ascii file.  Many numeric 
processing applications now have the ability to read Netcdf files 
and subsets directly.  HTH.
--Dave

On 4/15/2011 1:02 PM, Lucas.Moxey wrote:
Dear netcdfgroup community

I'm trying to extract some data from a netcdf file I have. The file
has various dimensions & variables, these being (hereby summarized):

dimensions:
time = 216 ; (note: these are the number of months)
depth = 1 ;
lat = 60 ;
lon = 97 ;

variables:
float time(time) ;
float depth(depth) ;
float lat(lat) ;
float lon(lon) ;
float u(time, depth, lat, lon) ;
float v(time, depth, lat, lon) ;

I'm a bit confused... how can I specifically extract the data for
the "u" variable specifically for time #3 (e.g.: month 3) in ascii
format? I'm confused on how to do this... I've been trying ncdump,
but haven't quite made it work. Currently, I'm using netcdf v3.5.0.

Any thoughts on this would be very helpful. Thanks!

Lucas

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