RE: Manipulating netCDF files (ncdigest V1 #922)

• To: netcdfgroup@xxxxxxxxxxxxxxxx
• Subject: RE: Manipulating netCDF files (ncdigest V1 #922)
• From: Takeshi Horinouchi <horinout@xxxxxxxxxxxxxxxxxx>
• Date: Mon, 14 Nov 2005 11:41:56 +0900

> The replies are providing an interesting comparison of packages for
> manipulating netCDF files.

I would add an example using Ruby, which is an object-oriented
language like Python.

% cat edit_nc.rb
require 'numru/netcdf'
include NumRu               # Or use NumRu::NetCDF instead of NetCDF below
file = NetCDF.open('G.nc','a')      # 'a' (append) or 'r+' like fopen in C
x = file.var('X')
val = x.get
val[ val.eq(32.0) ] = 45.0
x.put(val)
file.close

Here, I use the same netcdf file as a privious reporter used, but
the program works regardress the rank (# of dimensions) of the
varibale.

% ncdump G.nc
netcdf G {
dimensions:
        d = 8 ;

variables:
        float X(d) ;

data:

 X = 27 , 32.5 , 32 , 30.1 , 29 , 40 , 32 , 45  ;
}

% ruby edit_nc.rb

% ncdump G.nc
netcdf G {
dimensions:
        d = 8 ;

variables:
        float X(d) ;

data:

 X = 27 , 32.5 , 45 , 30.1 , 29 , 40 , 45 , 45  ;
}

--
Takeshi Horinouchi  (Kyoto Univ.)

> 
> Here is my solution using (and shameless plug for) NAP (a.k.a. tcl-nap),
> whose home is
> http://tcl-nap.sourceforge.net
> 
> I wrote the following shell script named 'change_nc_value':
> 
> $ cat change_nc_value   
> #!/bin/sh
> tclsh << END
> nap "in = [nap_get netcdf $1 $2]"
> [nap "in == $3 ? $4 : in"] netcdf $1 $2
> END
> 
> I then tested it as follows:
> 
> $ ncdump G.nc
> netcdf G {
> dimensions:
>         d = 8 ;
> variables:
>         float X(d) ;
> data:
> 
>  X = 27, 32.5, 32, 30.1, 29, 40, 32, 45 ;
> }
> $ change_nc_value G.nc X 32 45
> $ ncdump G.nc
> netcdf G {
> dimensions:
>         d = 8 ;
> variables:
>         float X(d) ;
> data:
> 
>  X = 27, 32.5, 45, 30.1, 29, 40, 45, 45 ;
> }
> 
> Harvey Davies, CSIRO Marine and Atmospheric Research,
> Private Bag No. 1, Aspendale 3195
> E-mail: harvey.davies@xxxxxxxx
> Office: 03 9239 4556
> Mobile: 04 2241 7563
> 
>   > -----Original Message-----
>   > From: owner-ncdigest@xxxxxxxxxxxxxxxx [mailto:owner-
>   > ncdigest@xxxxxxxxxxxxxxxx]
>   > Sent: Saturday, 12 November 2005 15:25
>   > To: ncdigest@xxxxxxxxxxxxxxxx
>   > Subject: ncdigest V1 #922
>   > 
>   > 
>   > ncdigest           Friday, November 11 2005           Volume 01 :
> Number
>   > 922
>   > 
>   > 
>   > 
>   > Today's Topics:
>   > Manipulating netCDF files
>   > Re: Manipulating netCDF files
>   > Re: Manipulating netCDF files
>   > Re: Manipulating netCDF files
>   > Re: Manipulating netCDF files
>   > RE: Manipulating netCDF files
>   > 
>   >
> ----------------------------------------------------------------------
>   > 
>   > Date: Fri, 11 Nov 2005 07:32:16 -0600
>   > From: "Waylon.Collins" <Waylon.Collins@xxxxxxxx>
>   > Subject: Manipulating netCDF files
>   > 
>   > Dear group members,
>   > 
>   > After reviewed the Unidata list of software that manipulates netCDF
>   > files, I have yet to find one that can perform the following task --
> I
>   > need command-line software (that can run in a Redhat Enterprise
> Linux
>   > environment) that will allow me to replace data values, associated
> with
>   > a particular variable, with values that I can specify. It needs to
> allow
>   > for a logical operation. For example, the software needs to be able
> to
>   > perform the following -- "Any datum of variable X, within netCDF
> file
>   > with filename F.nc, that equals 32, change it to the value 45. Thus,
> the
>   > original file F.nc is now altered, or the altered file is now named
>   > G.nc". Any help will be greatly appreciated.
>   > 
>   > Sincerely,
>   > 
>   > Waylon
>   > 
>   > - --
>   >
> **********************************************************************
>   > * Waylon G. Collins                  Voice: (361)289-0959
> *
>   > * NOAA/National Weather Service      E-Mail: Waylon.Collins@xxxxxxxx
> *
>   > * 300 Pinson Drive
> *
>   > * Corpus Christi, TX 78406
> *
>   > * USA
> *
>   >
> **********************************************************************

• References:
  • RE: Manipulating netCDF files (ncdigest V1 #922)
    • From: Harvey.Davies