Write netcdf file using matlab native functions

Check the help page from Mathworks for new version Matlab Please leave your comments to help improve the code in the future. Your help is greatly appreciated! function SaveNcVarMatlab(ncfile,ncvar,MagicTag,myValue,myDType) % to save a variable to a netcdf file using native matlab netcdf-functions % Usage: SaveNcVarMatlab(nc-filename,nc-varname,MagicTag,myValue,[myDType]) % e.g., % 1: to save a 4D data %     SaveNcVarMatlab('mask.nc','tmask',{'t','z','y','x'},4D-data,'float'); %     if the nc-file exist, the code will try to append data to old %     file as long as the dimensions of input data is consistent %     with existing one. If necessary, new dimensions will be added %     automatically. % 2: to add an attribute to an variable in existing nc file %     SaveNcVarMatlab('mask.nc','tmask','att','long_name','mask at t-point') %     Will overwrite existing one automatically. If no value set to %     the attribute, the code will try to delete that attribute. % 3: add/delete a global attribute, similar to the second example %     but won't use ncvar here. % Note: %    Overwriting an existing variable is possible but disabled in %    this version. Also unlimited dimension is not considered %    here. % copyright @ http://scriptdemo.blogspot.com % ref: matlab netcdf help if nargin<4 help SaveNcVarMatlab; return; end if iscell(MagicTag)     if nargin~=5         help SaveNcVarMatlab         return     end elseif ischar(MagicTag)     if ischar(myValue)        tmpstr=myValue; clear myValue        myValue.name=tmpstr; clear tmpstr        if nargin==5           myValue.value=myDType;        else            myValue.value='';        end     elseif isstruct(myValue)        if ~isfield(myValue,'name')            help SaveNcVarMatlab;            return;        else            if ~isfield(myValue,'value')               if nargin==5                  myValue.value=myDType;               else                  myValue.value='';               end            end        end     elseif ~isstruct(myValue)         disp('Not valid value for myValue.')         help SaveNcVarMatlab         return     end end % to support my work, please keep the "creator" global attribute mycreatorstr='SaveNcVarMatlab.m from http://scriptdemo.blogspot.com'; if iscell(MagicTag) % add values   [ncfid,IsAppend,OldNC,IsOldVar,OldVar]=CheckNCExist(ncfile,ncvar);   if length(MagicTag)==1       myValue=reshape(myValue,[],1);       vardiminput=length(myValue);   else      vardiminput=size(myValue);   end   if IsAppend      for nd=1:length(MagicTag)         if sum(ismember(OldNC.dimname,MagicTag{nd}))==0            myDim.name{nd}=MagicTag{nd};            myDim.len(nd)=vardiminput(nd);            myDim.IsNew(nd)=1;         else            dim_loc=find(ismember(OldNC.dimname,MagicTag{nd})==1);            if OldNC.dimlen(dim_loc)~=vardiminput(nd)               disp(['The length of input dimension ',MagicTag{nd},' is not the same as the exist one'])               return               % should consider unlimite dimension in the future            else               myDim.name{nd}=MagicTag{nd};               myDim.ID(nd)=OldNC.dimid(dim_loc);               myDim.IsNew(nd)=0;            end         end      end   else      for nd=1:length(MagicTag)          myDim.name{nd}=MagicTag{nd};          myDim.len(nd)=vardiminput(nd);          myDim.IsNew(nd)=1;      end   end   if IsOldVar      % support overwrite???      netcdf.abort(ncfid); return   else      if IsAppend netcdf.reDef(ncfid); end      % define some new dimension      for nd=1:length(myDim.name)          if myDim.IsNew(nd)             myDim.ID(nd)=netcdf.defDim(ncfid,myDim.name{nd},myDim.len(nd));          end      end      myvarid=netcdf.defVar(ncfid,ncvar,myDType,fliplr(myDim.ID));      netcdf.putAtt(ncfid,netcdf.getConstant('NC_GLOBAL'),'creator',mycreatorstr);      netcdf.endDef(ncfid);      %netcdf.putVar(ncid,varid,start,count,stride,data)      myValue=permute(myValue,length(size(myValue)):-1:1);      netcdf.putVar(ncfid,myvarid,myValue);   end elseif ischar(MagicTag)   [ncfid,IsAppend,OldNC,IsOldVar,OldVar]=CheckNCExist(ncfile,ncvar);   if IsAppend      switch lower(MagicTag)        case {'a','attribute','var_attribute','vatt','att'}          if IsOldVar             OldVar=GetVAtts(ncfid,OldVar);             netcdf.reDef(ncfid);             if isfield(OldVar,'attname')                if ~isstruct(myValue) %delete attribute                    if sum(ismember(OldVar.attname,myValue))==1                       netcdf.delAtt(ncfid,OldVar.varid,myValue);                    else                        disp(['attribute: ',myValue,' not exist. Nothing is done'])                        netcdf.abort(ncfid); return;                    end                else                   if sum(ismember(OldVar.attname,myValue.name))==1                      %netcdf.delAtt(ncfid,OldVar.varid,myValue.name);                      if isempty(myValue.value)                         netcdf.delAtt(ncfid,OldVar.varid,myValue.name);                      else                         % overwrite old one automatically                         netcdf.putAtt(ncfid,OldVar.varid,myValue.name,myValue.value);                      end                   else                      %new attribute                      if ~isempty(myValue.value)                        netcdf.putAtt(ncfid,OldVar.varid,myValue.name,myValue.value);                      end                   end                end             else               %new attribute               if ~isempty(myValue.value)                  netcdf.putAtt(ncfid,OldVar.varid,myValue.name,myValue.value);               end             end          else             disp(['var: ',ncvar,' isn''t exist in ',ncfile]);             netcdf.abort(ncfid);             return          end        case {'ga','global_attribute','gatt'}          OldNC=GetGAtts(ncfid,OldNC);          netcdf.reDef(ncfid);          if ~isstruct(myValue)              if isfield(OldNC,'attname')                 if sum(ismember(OldNC.attname,myValue))==1                    netcdf.delAtt(ncfid,netcdf.getConstant('GLOBAL'),myValue);                 else                    disp(['attribute: ',myValue,' not exist. Nothing is done'])                    netcdf.abort(ncfid); return;                 end              else                 disp('No global attributes available.')                 netcdf.abort(ncfid); return;              end          else             if isfield(OldNC,'attname')                if sum(ismember(OldNC.attname,myValue.name))==1                   netcdf.delAtt(ncfid,netcdf.getConstant('GLOBAL'),myValue.name);                   if ~isempty(myValue.value)                      netcdf.putAtt(ncfid,netcdf.getConstant('NC_GLOBAL'),myValue.name,myValue.value);                   end                else                   %new global attribute                   if ~isempty(myValue.value)                      netcdf.putAtt(ncfid,netcdf.getConstant('NC_GLOBAL'),myValue.name,myValue.value);                   end                end             else                % also new global attribute                if ~isempty(myValue.value)                   netcdf.putAtt(ncfid,netcdf.getConstant('NC_GLOBAL'),myValue.name,myValue.value);                else                   netcdf.abort(ncfid); return;                end             end          end        otherwise            disp(['Not defined attribute type: MagicTag: ',MagicTag])            netcdf.abort(ncfid); return;      end   else      netcdf.abort(ncfid);      disp([ncfile,' dos not exist, global attribute can''t be added.'])      return   end   netcdf.putAtt(ncfid,netcdf.getConstant('NC_GLOBAL'),'creator',mycreatorstr);   netcdf.endDef(ncfid); else   disp('Not valid value for MagicTag')   return; end %close the file netcdf.close(ncfid); end function [ncfid,IsAppend,OldNC,IsOldVar,OldVar]=CheckNCExist(ncfile,ncvar)   IsAppend=0; IsOldVar=0;   if exist(ncfile,'file')      disp([ncfile,' already exist, try the append mode']);      IsAppend=1;   end   % Open the nc file   if IsAppend      ncfid=netcdf.open(ncfile,'NC_WRITE');      [OldNC.numdims, OldNC.numvars, OldNC.numGAtt, unlimdimID] = netcdf.inq(ncfid);      for NDim=1:OldNC.numdims         [OldNC.dimname{NDim}, OldNC.dimlen(NDim)] = netcdf.inqDim(ncfid,NDim-1);         OldNC.dimid(NDim)=NDim-1;      end      for NVar=1:OldNC.numvars         [tmpvarname, tmpvarxtype,tmpvardims, tmpvarnumatts] = netcdf.inqVar(ncfid,NVar-1);         if strcmp(tmpvarname,ncvar)             IsOldVar=1;             OldVar.varid=NVar-1;             OldVar.varname=tmpvarname;             OldVar.varxtype=tmpvarxtype;             OldVar.vardimids=tmpvardims;             OldVar.numatts=tmpvarnumatts;             break;         end      end      if IsOldVar==0 OldVar=nan; end   else      ncfid=netcdf.create(ncfile,'NC_NOCLOBBER');      OldNC=nan; OldVar=nan;   end end function OldVar=GetVAtts(ncfid,OldVar)   for numA=1:OldVar.numatts       OldVar.attname{numA}=netcdf.inqAttName(ncfid,OldVar.varid,numA-1);       % OldVar.attid(numA)=netcdf.inqAttID(ncfid,varid,OldVar.attname{numA});   end end function OldNC=GetGAtts(ncfid,OldNC)   for numA=1:OldNC.numGAtt       OldNC.attname{numA}= netcdf.inqAttName(ncfid,netcdf.getConstant('NC_GLOBAL'),numA-1);   end end