nc2ascii

 PURPOSE: export timeslice of CF-1 conform (climate) data grid to ArcGIS
 ASCII format.
 -------------------------------------------------------------------
 USAGE: nc2ascii(ncin, fout, time, varids)
 where: ncin is the path of the netcdf input file(string) or ncID (int),
        fout is the output ascii filename (string), 
        time is the timeslice to read in (int, opional, default 1) 
        and varids is a vector of variable IDs in the from [varID, latID,lonID]
        giving the variable IDs of the variable to export
        along with the IDs of aviables storing the latitude and longitude 
        information. Default is [end,2,4] (end=last var in file).

 Note: Quick'n'dirty. Adapt to your need (e.g. using varnames).

 Uses: mat2asciigrid(), nc_readvar()

       MEXCDF:  http://mexcdf.sourceforge.net
       and obviously netcdf: http://www.unidata.ucar.edu/s(oftware/netcdf/

  Felix Hebeler, Geography Dept., University Zurich, December 2006.
some checking first

0001 function nc2ascii(ncin, fout, time, varids)
0002 % PURPOSE: export timeslice of CF-1 conform (climate) data grid to ArcGIS
0003 % ASCII format.
0004 % -------------------------------------------------------------------
0005 % USAGE: nc2ascii(ncin, fout, time, varids)
0006 % where: ncin is the path of the netcdf input file(string) or ncID (int),
0007 %        fout is the output ascii filename (string),
0008 %        time is the timeslice to read in (int, opional, default 1)
0009 %        and varids is a vector of variable IDs in the from [varID, latID,lonID]
0010 %        giving the variable IDs of the variable to export
0011 %        along with the IDs of aviables storing the latitude and longitude
0012 %        information. Default is [end,2,4] (end=last var in file).
0013 %
0014 % Note: Quick'n'dirty. Adapt to your need (e.g. using varnames).
0015 %
0016 % Uses: mat2asciigrid(), nc_readvar()
0017 %
0018 %       MEXCDF:  http://mexcdf.sourceforge.net
0019 %       and obviously netcdf: http://www.unidata.ucar.edu/s(oftware/netcdf/
0020 %
0021 %  Felix Hebeler, Geography Dept., University Zurich, December 2006.
0022 %some checking first
0023 if exist(ncin)    % check if ncin exists as path or id
0024     if isstr(ncin)
0025         if ~exist(ncin, 'file')
0026             error(['Netcdf file not found: ',ncin])
0027         else
0028             ncid=mexcdf('OPEN',ncin,'r'); % open existing file
0029         end
0030     elseif isinteger(ncin)
0031         [a,a,a,a,a] = mexnc('inq', ncin )
0032         if a~=0  % if status a is anything but 0, there's an error:
0033             error(mexnc('strerror',a)) 
0034         end
0035     end
0036 else 
0037    error('No valid Netcdf input file referrer specified')    
0038 end
0039 % some more checking for defaults
0040 if ~exist('time')
0041     time=1;
0042 end
0043 if ~exist('varids')
0044     [ndims, nvars] = mexcdf('INQUIRE',ncid);  % retrieve info
0045     varids=[nvars-1,2,4];
0046 end
0047 [varname, datatype] = mexnc('inq_var', ncid, varids(1)) ;
0048 %mexcdf('CLOSE',ncid);
0049 data=nc_readvar(ncin,varname,time);
0050 data=rot90(data,3);
0051 data=fliplr(data);
0052 tlat=mexnc('get_var_float',ncid,varids(2)); %read in lat and lon as float
0053 tlon=mexnc('get_var_float',ncid,varids(3));
0054 
0055 mat2asciigrid(fout, tlon,tlat,data);
0056 %figure, imagesc(tlon(end:-1:1),tlat,fliplr(data)) %
0057 %set(gca,'ydir','normal')
0058 %title('NetCDF grid successfully exported to ArcGrid ASCII Format:')