NCL: Write netCDF4 string data

Support for NetCDF-4 files is in beta-testing in V6.1.1.
We encourage people to test it out and give us feedback on our ncl-talk email list.

Below is a script which demonstrates how to read/write NetCDF4 string data.

Read NetCDF4 string data from a file generated from NetCDF string example code.

 fn = "$NCARGTEST/nclscripts/nc4_files/strings.nc"

 fori= addfile(fn, "r")

;print(fori)
;printVarSummary(fori)

 strs = fori->universal_declaration_of_human_rights

;print(strs)

Create a file to write NetCDF4 string data.

;===================================================================
 setfileoption("nc", "Format",  "NetCDF4")

 fn = "nc4_wrt_string.nc"
 system("/bin/rm -f " + fn)
 fo = addfile(fn, "c")

Define some file attributes:

;===================================================================
 fAtt               = True
 fAtt@title         = "NCL generated netCDF 4 file"
 fAtt@source_file   = fn
 fAtt@Conventions   = "None"
 fAtt@creation_date = systemfunc("date")

;print(fAtt)

 fileattdef(fo, fAtt)

Define dimensions:

;===================================================================
 nstrs    = dimsizes(strs)
 dimNames = (/"Sentence"/)
 dimSizes = (/ nstrs    /)
 dimUnlim = (/ False    /)
 filedimdef(fo, dimNames, dimSizes, dimUnlim)

Define the variable:

;===================================================================
 strsdims = getvardims(strs)

 strsdims = "Sentence"

 filevardef(fo, "nc4_string", typeof(strs), strsdims)

Write the compound data out, and close the file:

;===================================================================
 fo->nc4_string = (/strs/)

 delete(fo)

This script produced (use "ncl_filedump nc4_wrt_string.nc"):

Variable: f
Type: file
filename:       nc4_wrt_string
path:   nc4_wrt_string.nc
attributes:
    creation_date       :       Mon Jan 28 10:21:01 MST 2013
    Conventions :       None
    source_file :       nc4_wrt_string.nc
    title       :       NCL generated netCDF 4 file

dimensions:
    Sentence    = 30

variables:
    nc4_string:         [ 30  ]