getnc.m

matlacb程序包

%
%   5) A strange 'feature' of matlab 5 is that it will not tolerate a singleton
% dimension as the final dimension of a multidimensional array.  Thus, if
% you chose to have only one element in the final dimension this dimension
% will be 'squeezed' whether you want it to be or not - this seems to be
% unavoidable.
%
%   6) Some earlier versions of this function the argument "order" to be an
% array. This option has been removed because it was so confusing - the
% matlab function "permute" can be used to do the same thing.
%
% EXAMPLES:
% 1) Get all the elements of the variable, note the order of the dimensions:
% >> airtemp = getnc('oberhuber.nc', 'airtemp');
% >> size(airtemp)
% ans =
%     12    90   180
%
% 2) Get a subsample of the variable, note the stride:
% >> airtemp = getnc('oberhuber.nc', 'airtemp', [-1 1 3], [-1 46 6], [1 5 1]);
% >> size(airtemp)
% ans =
%     12    10     4
%
% 3) Get all the elements of the variable, but with missing values
%    replaced with 1000.  Note that the bl_corner, tr_corner, stride and
%    order vectors have been replaced by -1 to choose the defaults:
% >> airtemp = getnc('oberhuber.nc', 'airtemp', -1, -1, -1, -1, 3, 1000); 
% >> size(airtemp)
% ans =
%     12    90   180
%
% 4) Get a subsample of the variable, a singleton dimension is squeezed:
% >> airtemp = getnc('oberhuber.nc', 'airtemp', [-1 7 -1], [-1 7 -1]);   
% >> size(airtemp)                                                         
% ans =
%     12   180
% 
% 5) Get a subsample of the variable, a singleton dimension is not squeezed:
% >> airtemp = getnc('oberhuber.nc','airtemp',[-1 7 -1],[-1 7 -1],-1,-1,-1,-1,0);
% >> size(airtemp)                                                            
% ans =
%     12     1   180
%
%
% AUTHOR:   J. V. Mansbridge, CSIRO
%---------------------------------------------------------------------

% This function calls: check_nc.m, check_st.m, fill_att.m, fill_var.m,
%                      getnc_s.m, inqnc.m, menu_old.m, mexnc, pos_cds.m,
%                      return_v.m, uncmp_nc.m, y_rescal.m

%     Copyright (C), J.V. Mansbridge, 1992
%     Commonwealth Scientific and Industrial Research Organisation
%     $Id: getnc.m Mon, 03 Jul 2006 17:16:40 $
% 
%--------------------------------------------------------------------

% In November 1998 some code was added to deal better with byte type data in a
% netcdf file. Note that any values greater than 127 will have 256 subtracted
% from them. This is because on some machines (an SGI running irix6.2 is an
% example) values are returned in the range 0 to 255. Note that in the fix the
% values less than 128 are unaltered and so we do not have to know whether the
% particular problem has occurred or not; for machines where there is no problem
% no values will be altered. This is applied to byte type attributes (like
% _FillValue) as well as the variable values.

% Check the number of arguments.  If there are no arguments then return
% the help message.  If there is more than one argument then call
% getnc_s which reads the netcdf file in a non-interactive way.
% If there is only one argument then drop through and find the values
% interactively.

num_args = length(varargin);
if num_args == 0
  % No input argument
  help getnc
  disp('You must pass an input argument to getnc')
  return
elseif num_args == 1
  if isstruct(varargin{1})
    % Send on to getnc_s
    values = getnc_s(varargin);
    return
  else
    % Carry on with the interactive version of getnc
    file = varargin{1};
  end
else
  % Send on to getnc_s
  values = getnc_s(varargin);
  return
end

% Find the full path name of the file.

[cdf, file_status] = CSIRO_get_more_file_info(file);

% Find out whether values should be automatically rescaled or not.

[rescale_var, rescale_att] = y_rescal;

% Get the dds for the file.

desc = ddsnc(cdf);

% varstring = fill_var(cdfid, nvars);

% Prompt the user for the name of the variable containing the hyperslab.

nvars = length(desc.variable);
list_variable_name = cell(nvars, 1);
for ii = 1:nvars
  list_variable_name{ii} = desc.variable(ii).name;
end
i_var = menu('Choose a variable', list_variable_name);

% Get attribute and dimension information for the chosen variable.

var_name = list_variable_name{i_var};
[att_val, att_name_list] = attnc(cdf, var_name);
dim_idents = desc.variable(i_var).dim_idents;
num_dims_of_var = length(dim_idents);
list_dim_name = cell(num_dims_of_var, 1);
list_dim_length = zeros(num_dims_of_var, 1);
is_dim_a_variable = zeros(num_dims_of_var, 1);
for ii = 1:num_dims_of_var
  list_dim_name{ii} = desc.dimension(dim_idents(ii)).name;
  list_dim_length(ii) = desc.dimension(dim_idents(ii)).length;
  for jj = 1:nvars
    if strcmp(list_dim_name{ii}, list_variable_name{jj})
      is_dim_a_variable(ii) = 1;
      break
    end
  end
end

% Call simple input dialog so user can select the features they need. Note
% that this is in a loop in case the user messes up the answer.

dlg_title = [var_name ': input details'];
num_lines = 1;
for ii = 1:num_dims_of_var
  prompt{ii} = [list_dim_name{ii} ...
		': [starting index, finishing index, stride]'];
  defAns{ii} = ['[1, ' num2str(list_dim_length(ii)) ', 1]'];
end
ndvp = num_dims_of_var + 1;
prompt{ndvp} = 'replace missing values with NaN? (y or n)';
defAns{ndvp} = 'y';

Resize = 'on';
repeat_loop = 1;
while repeat_loop
  
  % Get user respnse
  
  answer = inputdlg(prompt, dlg_title, num_lines, defAns, Resize);

  % Now parse the reply to see if it is o.k.
  
  repeat_loop = 0;
  for ii = 1:num_dims_of_var
    try
      xx = str2num(answer{ii});
      bl_corner(ii) = xx(1);
      tr_corner(ii) = xx(2);
      stride(ii) = xx(3);
    catch
      repeat_loop = repeat_loop + 1;
      err_msg{repeat_loop} = ['Dimension ' list_dim_name{ii} ...
		    ': specify [starting index, finishing index, stride]'];
    end
    switch lower(answer{ndvp})
     case 'y'
      change_miss = 2;
     case 'n'
      change_miss = 1;
     otherwise
      repeat_loop = repeat_loop + 1;
      err_msg{repeat_loop} = 'Replacement of missing values specified wrongly';
    end
  end
  
  % Deal with any errors that the user made in the dialog box.
  
  if repeat_loop == 1
    errordlg(err_msg{1}, 'Error specifying array')
  elseif repeat_loop > 1
    clear err_list
    err_list{1} = ['There were ' num2str(repeat_loop) ' errors in the input' ...
		   ' dialog box'];
    for ii = 1:repeat_loop
      err_list{ii + 1} = err_msg{ii};
    end
    errordlg(err_list, 'Error specifying array')
  end
end
values = getnc(cdf, var_name, bl_corner, tr_corner, stride, -1, change_miss, ...
		    0, 1);