Re: How to create a new nc file

http://www.ncl.ucar.edu/Document/Functions/Contributed/region_ind.shtml

Please see Example 1.

The example file is a grib file but you can use a netCDF file.

====
   load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/contributed.ncl"
        ;
        ;
   f = addfile("NARRmonhr-b_221_20021201_2100_000.grb" , "r")

   glon2d = f->gridlon_221
   glat2d = f->gridlat_221

   printMinMax(glat2d, True)
   printMinMax(glon2d, True)

   latS = 30 ; California [*rough*]
   latN = 43
   lonL = -125
   lonR = -113

   ji = region_ind (glat2d,glon2d, latS, latN, lonW, lonE)

    jStrt = ji(0) ; lat start
    jLast = ji(1) ; lat last
    iStrt = ji(2) ; lon start
    iLast = ji(3) ; lon last

    LAT2D = glat2d(jStrt:jLast,iStrt:iLast)
    LON2D = glon2d(jStrt:jLast,iStrt:iLast)

   printMinMax(LAT2D, True)
   printMinMax(LON2D, True)

                       ; read data just for the region of interest
    x = f->LHTFL_221_SFC_113(:,jStrt:jLast,iStrt:iLast)

; write netCDF

        system("/bin/rm -f simple.nc") ; remove any pre-existing file
        ncdf = addfile("simple.nc" ,"c") ; open output netCDF file

     ; make time and UNLIMITED dimension
       ;filedimdef(ncdf,"time",-1,True)

     ; output regional variables directly
        ncdf->lat2d = LAT2D
        ncdf->lon2d = LON2D
        ncdf->LHTFL = x

On 5/17/11 2:06 PM, wei chih chen wrote:
> Dear NCL users,
> I have a NARR nc file, and I just want to narrow down to the specific
> area I want. I have boundary of lat and lon for the new area. How can I
> extract the area I want and save it to a new nc file without missing
> other variables? Any command can do this? Thank you.
>
> --
> Best regards
> Wei-Chih
>
>
>
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Received on Tue May 17 16:56:01 2011