Add a useful package (from Source forge) for octave

[CreaPhase.git] / octave_packages / octcdf-1.1.4 / example_netcdf.m

diff --git a/octave_packages/octcdf-1.1.4/example_netcdf.m b/octave_packages/octcdf-1.1.4/example_netcdf.m
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+%% Copyright (C) 2005 Alexander Barth
+%%
+%% This program is free software; you can redistribute it and/or modify
+%% it under the terms of the GNU General Public License as published by
+%% the Free Software Foundation; either version 2 of the License, or
+%% (at your option) any later version.
+%%
+%% This program is distributed in the hope that it will be useful,
+%% but WITHOUT ANY WARRANTY; without even the implied warranty of
+%% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+%% GNU General Public License for more details.
+%%
+%% You should have received a copy of the GNU General Public License
+%% along with this program; If not, see <http://www.gnu.org/licenses/>.
+
+% Example for creating and reading a netcdf file
+
+
+% create some variables to store them in a netcdf file
+
+latitude = -90:1:90;
+longitude = -179:1:180;
+[y,x] = meshgrid(pi/180 * latitude,pi/180 * longitude);
+temp = cos(2*x) .* cos(y);
+
+%---------------------------------------%
+%                                       %
+% write data to a netcdf file           %
+%                                       %
+%---------------------------------------%
+
+% create netcdf file called example.nc
+
+nc = netcdf('example.nc','c');
+
+% define the dimension longitude and latitude of size
+% 360 and 181 respectively.
+
+nc('longitude') = 360;
+nc('latitude') = 181;
+
+% coordinate variable longitude
+
+nc{'longitude'} = ncdouble('longitude');              % create a variable longitude of type double with 
+                                                      % 360 elements (dimension longitude).
+nc{'longitude'}(:) = longitude;                       % store the octave variable longitude in the netcdf file
+nc{'longitude'}.units = 'degrees_east';                % define a string attribute of the variable longitude
+
+% coordinate variable latitude
+
+nc{'latitude'} = ncdouble('latitude');;               % create a variable latitude of type double with 
+                                                      % 181 elements (dimension latitude).                
+nc{'latitude'}(:) = latitude;                         % store the octave variable latitude in the netcdf file
+nc{'latitude'}.units = 'degrees_north';                % define a string attribute of the variable latitude
+
+% variable temp
+
+nc{'temp'} = ncdouble('latitude','longitude');        % create a variable temp of type double of the size 360x181 
+                                                      % (dimension longitude and latitude).    
+nc{'temp'}(:) = temp;                                 % store the octave variable temp in the netcdf file
+nc{'temp'}.long_name = 'Temperature';                 
+nc{'temp'}.units = 'degree Celsius';                  % define a string attribute of the variable
+nc{'temp'}.valid_range = [-10 40];                    % define a vector of doubles attribute of the variable
+
+                                                      % define a global string attribute
+nc.history = 'netcdf file created by example_netcdf.m in octave';
+nc.title = 'sample file';
+
+close(nc)                                             % close netcdf file and all changes are written to disk
+
+
+disp(['example.nc file created. You might now inspect this file with the shell command "ncdump -h example.nc"']);
+
+
+%---------------------------------------%
+%                                       %
+% read data from a netcdf file          %
+%                                       %
+%---------------------------------------%
+
+nc = netcdf('example.nc','r');                       % open netcdf file example.nc in read-only
+
+n = nc('longitude');                                 % get the length of the dimension longitude
+
+temp = nc{'temp'}(:);                                % retrieve the netcdf variable temp
+temp_units = nc{'temp'}.units;                       % retrieve the attribute units of variable temp
+temp_valid_range = nc{'temp'}.valid_range;           % retrieve the attribute valid_range of variable temp
+
+global_history = nc.history;                         % retrieve the global attribute history