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[netCDF #CPI-418355]: Problems writing variables in netcdf 4.1.2

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  • Subject: [netCDF #CPI-418355]: Problems writing variables in netcdf 4.1.2
  • Date: Tue, 12 Apr 2011 20:27:09 -0600
Hi Lara,

> I have recently starting using netcdf 4.1.2. in ifort on my Mac. I have
> managed to build the code and have successfully managed to read in some
> existing netcdf files, however I am having great difficulty writing to a
> netcdf file. I get stuck on the step where I define my variables.
> 
> I have written a very basic program to try to check that this is
> working. I can write a single dimension variable but cannot write
> multiple dimensional variables. I have basically copied a program from
> the examples on your website and tried to change it for my use.
> 
> Ignoring all my definitions for now, I have
> 
> call check (nf90_create(filename, nf90_clobber,ncid))
> 
> call check (nf90_def_dim(ncid, 'lat', 90, lat_id))
> call check (nf90_def_dim(ncid,'lon',180,lon_id))
> 
> call check (nf90_def_var (ncid,'latitude',nf90_real,lat_id,latitude))
> call check (nf90_def_var (ncid,'longitude',nf90_real,lon_id,longitude))
> 
> This all works fine but if I try to define a variable with lat_id,lon_id
> it doesn't compile
> 
> call check
> (nf90_def_var(ncid,'concentration',nf90_real,(lon_id,lat_id),concentration))

With a compiler that supports Fortran-90 or later, you should be able to use
the following syntax for an array of dimids:

  call check(nf90_def_var(ncid,'concentration',nf90_real, (/ lon_id,lat_id /), 
concentration))

as in the Fortran-90 examples here:

  http://www.unidata.ucar.edu/netcdf/examples/programs/

Note the "(/" and "/)" syntax required for an array list constant, but you can 
also use a
named variable to hold the dimension IDs, as in

  integer :: dimids(NDIMS)
...
  ! The dimids array is used to pass the dimids of the dimensions of
  ! the netCDF variables. Both of the netCDF variables we are creating
  ! share the same four dimensions. In Fortran, the unlimited
  ! dimension must come last on the list of dimids.
  dimids = (/ lon_id, lat_id /)
 ...
  call check(nf90_def_var(ncid,'concentration',nf90_real, dimids, 
concentration))

--Russ

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



Ticket Details
===================
Ticket ID: CPI-418355
Department: Support netCDF
Priority: Normal
Status: Closed