netcdf.m

MATLAB中读写、处理科学数据文件格式NETCDF的程序

%      ncexample() creates, populates, and reads a NetCDF file.
%      tnetcdf() exercizes the NetCDF Toolbox extensively.
%
%   WWW: <http://crusty.er.usgs.gov/~cdenham/MexCDF/nc4ml5.html>.
%
% <<<<<<<<<<<<<<<<< End of NetCDF Language Synopsis >>>>>>>>>>>>>>>>>
 
% Copyright (C) 1996-7 Dr. Charles R. Denham, ZYDECO.
%  All Rights Reserved.
%   Disclosure without explicit written consent from the
%    copyright owner does not constitute publication.

% Updated    18-Aug-1997 09:39:52.
% Updated    20-May-1999 09:33:04.
% Updated    24-Aug-1999 09:12:11.
% Updated    10-Apr-2000 21:07:48.

ncwhatsnew

if nargin == 1 & nargout < 1 & isequal(theFilename, 'version')
	version(ncitem)
	return
end

if nargin < 1 & nargout < 1
   help(mfilename)
   ncversion
   disp(' ')
   return
end

if nargout > 0, self = []; end

% Open with dialog as 'nowrite'.

if nargout > 0 & nargin < 1
   result = netcdf('nowrite');
   if ~isempty(result)
      ncregister(result)
      result = ncregister(result);
   end
   self = result;
   return
end

if nargin < 2, thePermission = ''; end

result = [];

% Randomly named file.

if nargin == 1 & strcmp(theFilename, 'random')
   result = [];
   count = 0;
   while isempty(result) & count < 32
		thePWD = pwd;
		if thePWD(length(thePWD)) ~= filesep
			thePWD = [thePWD filesep];
		end
      theFilename = [thePWD 'temp' int2str(rand(1, 1) .* 10000) '.nc'];
      result = netcdf(theFilename, 'noclobber');
   end
   if ~isempty(result)
      ncregister(result)
      result = ncregister(result);
   end
   if nargout > 0
      self = result;
   else
      ncans(result)
   end
   return
end

if nargin == 1
   switch class(theFilename)
   case 'double'
      theNCid = theFilename;
      theStruct.itsPermission = 'unknown';
      theStruct.itsDefineMode = 'unknown';
      theStruct.itsFillMode = 'unknown';
      theStruct.itsMaxNameLen = 0;
      result = class(theStruct, 'netcdf', ncitem('', theNCid));
      result = ncregister(result);
      if nargout > 0
         self = result;
      else
         ncans(result)
      end
      return
   case 'char'
      thePermission = '';
      thePerm = ncpermission(theFilename);
      switch thePerm
      case {'nowrite', 'write', 'noclobber', 'clobber', ...
            'readonly', 'define'}
         thePermission = thePerm;
         theFilename = '*';
      otherwise
         thePermission = 'nowrite';
      end
   otherwise
      return
   end
end

if isempty(thePermission), thePermission = 'nowrite'; end

if any(theFilename == '*')
   switch thePermission
   case {'noclobber', 'clobber'}
		theSuggested = theFilename;
		if isequal(theFilename, '*')
			theSuggested = 'unnamed.nc';
		else
			theSuggested(theSuggested == '*') = '';
		end
      [theFile, thePath] = uiputfile(theSuggested, 'Save NetCDF As');
      if ~any(theFile), return, end
   case {'nowrite', 'write', 'readonly', 'define'}
      [theFile, thePath] = uigetfile(theFilename, 'Select NetCDF File');
      if ~any(theFile), return, end
   otherwise
      return
   end
   theFilename = [thePath theFile];
   result = netcdf(theFilename, thePermission);
   if ~isempty(result)
      ncregister(result)
      result = ncregister(result);
   end
   if nargout > 0
      self = result;
   else
      ncans(result)
   end
   return
end

thePermission = ncpermission(thePermission);

switch thePermission
case 'define'
   result = netcdf(theFilename, 'write');
   if ~isempty(result), redef(result), end
   if nargout > 0
      self = result;
   else
      ncans(result)
   end
   return
otherwise
end

theDefineMode = '';
theFillMode = 'fill';   % The NetCDF default.
theMaxNameLen = 0;

theStruct.itsPermission = thePermission;
theStruct.itsDefineMode = theDefineMode;
theStruct.itsFillMode = theFillMode;
theStruct.itsMaxNameLen = theMaxNameLen;

result = class(theStruct, 'netcdf', ncitem(theFilename));

switch thePermission
case {'clobber', 'noclobber'}
   result = create(result, thePermission);
   if ncid(result) >= 0, theDefineMode = 'define'; end
case {'write', 'nowrite'}
   result = open(result, thePermission);
   if ncid(result) >= 0
      theDefineMode = 'data';
     elseif exist(name(result)) ~= 2
      result = open(result, 'clobber');
      if ncid(result) >= 0, theDefineMode = 'define'; end
   end
otherwise
   help netcdf
   warning([' ## No such permission: ' thePermission])
end

if ncid(result) >= 0
   result.itsDefineMode = theDefineMode;
   ncregister(result)
   result = ncregister(result);
  else
   disp([' ## NetCDF file not opened: ' theFilename])
   result = [];
end

if nargout > 0
   self = result;
else
   ncans(result)
end

function theResult = ncpermission(thePermission)

% netcdf/ncpermission -- Resolve permission string.
%  netcdf/ncpermission('thePermission') returns the NetCDF permission
%   string corresponding to 'thePermission', which may be uniquely
%   abbreviated.

thePerm = lower(thePermission);

% Lists of shortened permissions: must pre-allocate.

clobber = [];
noclobber = [];
write = [];
nowrite = [];
readonly = [];
define = [];

perms = {'clobber', 'noclobber', 'write', 'nowrite', 'readonly', 'define'};
for j = 1:length(perms)
   p = perms{j};
   c = cell(1, length(p));
   for i = 1:length(perms{j})
      c{i} = p;
      p(length(p)) = '';
   end
   eval([perms{j} ' = c;']);
end

% Formal name of thePermission.

switch thePerm
case clobber
   thePermission = 'clobber';
case noclobber
   thePermission = 'noclobber';
case write
   thePermission = 'write';
case [nowrite readonly]
   thePermission = 'nowrite';
case [define]
   thePermission = 'define';
otherwise
end

if nargout > 0, theResult = thePermission; end