[Matlab] show the variable information from a netcdf file

function myShowNc(ncFileName) % show information of a given netcdf file, similar to ncdump %          using matlab native netcdf functions % usage: %           myShowNc(netcdf-filename) % http://scriptdemo.blogspot.com if nargin==0    help myShowNc    return end if ~exist(ncFileName,'file')    error([ncFileName,' is not found!']); end ncfid=netcdf.open(ncFileName,'NC_NOWRITE'); % check dimensions [ndims,nvars,ngatts,unlimdimID] = netcdf.inq(ncfid); myncinfo.unLimID=unlimdimID; myncinfo.dimname=cell(ndims,1); myncinfo.dimlength=zeros(ndims,1); myncinfo.varname=cell(nvars,1); myncinfo.vardims=cell(nvars,1); myncinfo.varscale=ones(nvars,1); myncinfo.varoffset=zeros(nvars,1); disp(['netcdf file: ',ncFileName]) disp(' dimension:') for Ndim=1:ndims     [myncinfo.dimname{Ndim},myncinfo.dimlength(Ndim)]=netcdf.inqDim(ncfid,Ndim-1);     disp([' ',fixStrLen(myncinfo.dimname{Ndim},10),': ',num2str(myncinfo.dimlength(Ndim))]) end disp(' variables:') disp([' ',fixStrLen('var-name |',12,0),fixStrLen('var-dims',30,0),fixStrLen('scale',10,1),fixStrLen('offset',10,1)]) % check variables for nv=1:nvars     [myncinfo.varname{nv},myncinfo.vardims{nv}, ...      myncinfo.varscale(nv),myncinfo.varoffset(nv)]=getVarInfo(ncfid,nv-1,myncinfo);     disp([' ', fixStrLen([myncinfo.varname{nv},' |'],12) , fixStrLen(myncinfo.vardims{nv},30), ...                 fixStrLen(num2str(myncinfo.varscale(nv)),10,1),fixStrLen(num2str(myncinfo.varoffset(nv)),10,1)]) end netcdf.close(ncfid); %-------------------------------------------------------------------------------------- function outStr=fixStrLen(inStr,nLen,opt) % renamed to formatStr in another post. % if  opt == 0  'right-align' [default case] %     opt == 1  'center-align' %     opt == 2  'left-align' if nargin==1    nLen=0; elseif nargin==2    opt=0; elseif nargin~=3    help fixStrLen;    return end oriLen=length(inStr); if (oriLen>=nLen)     outStr=inStr; else     switch (opt)         case {0}             nSpace=nLen-oriLen;             outStr=[repmat(' ',1,nSpace),inStr];         case {1}           nSpace=ceil(0.5*(nLen-oriLen));           outStr=[repmat(' ',1,nSpace),inStr];           nSpace=nLen-oriLen-nSpace;           if (nSpace>0)              outStr=[outStr,repmat(' ',1,nSpace)];           end         case {2}             nSpace=nLen-oriLen;             outStr=[inStr,repmat(' ',1,nSpace)];         otherwise             disp('Unknown option');             return     end end function [varname,dimsStr,myScale,myOffSet]=getVarInfo(ncfid,varID,myncinfo) [varname,vartype,vardimids,numAtts]=netcdf.inqVar(ncfid,varID); myScale=1; myOffSet=0; for numA=1:numAtts     tmpattname=netcdf.inqAttName(ncfid,varID,numA-1);     switch lower(tmpattname)         case {'scale_factor','scalefactor'}            myScale=netcdf.getAtt(ncfid,varID,tmpattname);         case {'add_offset','off_set','offset','offset_value'}            myOffSet=netcdf.getAtt(ncfid,varID,tmpattname);         otherwise            % do nothing      end end % get dimStr if ~isempty(vardimids)    dimsStr=myncinfo.dimname{vardimids(1)+1};    for nd=2:length(vardimids)          dimsStr=[myncinfo.dimname{vardimids(nd)+1},' x ',dimsStr];    end else    dimsStr='unlimited'; end

[UPDATED] read netcdf file using native matlab functions

check the ncread for new version matlab from Mathworks. 
 
The attributes of scale factor, offset value and missing value are considered in this version.

function ncvardata=GetNcVarMatlab(ncfile,ncvar,RangeStr) % to read a variable from the netcdf file using native matlab netcdf-functions % Usage: vardata=GetNcVarMatlab(nc-filename,nc-varname,Dimension-Range) % e.g., %        mydata=GetNcVarMatlab('mask.nc','tmask','1:1,1:46,1:400,1:568'); %                      RangeStr here is similar to the output of ncdump % note: by default, variable will be converted into the class of double, %                      and the missing value will be converted into nan. % copyright @ http://scriptdemo.blogspot.com IsDebug=0; IsMissingNaN=1; % convert missing values into NaN if ~exist(ncfile,'file')    error([ncfile,' can not been found']);    return end ncfid=netcdf.open(ncfile,'NC_NOWRITE'); % get dimension length [numdims, numvars, numglobalatts, unlimdimID] = netcdf.inq(ncfid); for NDim=1:numdims    [dimname{NDim}, dimlen(NDim)] = netcdf.inqDim(ncfid,NDim-1); end %var infor varid=netcdf.inqVarID(ncfid,ncvar); [varname,varxtype,vardimids,NumAtts]=netcdf.inqVar(ncfid,varid); numdims=length(vardimids); % some variables may have less dimensions %check scale_factor & off_set IsRescale=0; IsMissing=0; myScale=1; myOffSet=0.0; for numA=1:NumAtts     tmpattname=netcdf.inqAttName(ncfid,varid,numA-1);     switch lower(tmpattname)        case {'scale_factor','scalefactor'}             IsRescale=1;             myscale=netcdf.getAtt(ncfid,varid,tmpattname);        case {'add_offset','off_set','offset'}             IsRescale=1;             myoffset=netcdf.getAtt(ncfid,varid,tmpattname);        case {'missing_value','missingvalue','missing'}             IsMissing=1;             mymissing=netcdf.getAtt(ncfid,varid,tmpattname);        otherwise             % do nothing     end end if IsRescale==1    if (myscale==1 & myoffset==0)       IsRescale=0;    end else    if ~exist('myscale','var') myscale=1; end    if ~exist('myoffset','var') myoffset=0; end end if ~exist('RangeStr','var')    RangeStr=':';    for nd=2:numdims        RangeStr=[RangeStr,',:'];    end end IndC=strfind(RangeStr,',');% index of commas if length(IndC)~=numdims-1    disp(['Input dimension range is not correct, should be: ',num2str(numdims),'-d']);    return end startstr=''; countstr=''; stridestr=''; for nn=1:length(IndC)+1     if nn==1        tmpstr=RangeStr(1:IndC(1)-1);     elseif nn<numdims        tmpstr=RangeStr(IndC(nn-1)+1:IndC(nn)-1);     else        tmpstr=RangeStr(IndC(nn-1)+1:end);     end     [tmpstart,tmpcount,tmpstride]=GetIndFromStr(tmpstr,':',dimlen(vardimids(numdims-nn+1)+1));     if nn==1         startstr=[num2str(tmpstart),'],'];         countstr=[num2str(tmpcount),'],'];         stridestr=[num2str(tmpstride),']'];     elseif nn==numdims         startstr=[',[',num2str(tmpstart),',',startstr];         countstr=['[',num2str(tmpcount),',',countstr];         stridestr=['[',num2str(tmpstride),',',stridestr];     else         startstr=[num2str(tmpstart),',',startstr];         countstr=[num2str(tmpcount),',',countstr];         stridestr=[num2str(tmpstride),',',stridestr];     end end if IsDebug    disp(['ncvardata=netcdf.getVar(ncfid,varid',startstr,countstr,stridestr,');']); end eval(['ncvardata=netcdf.getVar(ncfid,varid',startstr,countstr,stridestr,');']); netcdf.close(ncfid); ncvardata=permute(ncvardata,length(size(ncvardata)):-1:1); if IsRescale==1    %convert all data type into double    if ~strcmp(class(ncvardata),'double')       ncvardata=double(ncvardata);    end    if IsMissing       if IsMissingNaN==1; % convert missing values into NaN          ncvardata(ncvardata==mymissing)=nan;          ncvardata=ncvardata*double(myscale)+double(myoffset);       else          disp(['missing value for ',ncvar,' is ',num2str(mymissing)]);          %IndValid=find(ncvardata~=mymissing); length(IndValid)          %ncvardata(IndValid)=ncvardata(IndValid)*double(myscale)+double(myoffset);          ncvardata(ncvardata~=mymissing)=ncvardata(ncvardata~=mymissing)*double(myscale)+double(myoffset);       end    else       ncvardata=ncvardata*double(myscale)+double(myoffset);    end else   ncvardata=double(ncvardata); end function [numstart,numcount,numstride]=GetIndFromStr(tmpstr,ctag,Ndim) % Read the numbers from the special string IsDebug=0; IndC=strfind(tmpstr,ctag); if isempty(IndC)    numstart=str2double(tmpstr)-1;    numcount=1;    numstride=1; else   switch length(IndC)       case {1}           switch IndC             case {1} % : and :num                 if strcmp(tmpstr,':')                    numstart=0; numcount=Ndim; numstride=1;                 else                    if strcmp(tmpstr(2:end),'end')                     numstart=0; numcount=Ndim; numstride=1;                    else                     numstart=0; numcount=str2double(tmpstr(2:end))-1; numstride=1;                    end                 end             case {length(tmpstr)}                 if strcmp(tmpstr,':')                    numstart=0; numcount=Ndim; numstride=1;                    return                 else                    numstart=str2double(tmpstr(1:IndC-1))-1;                    numcount=Ndim-numstart;                    numstride=1;                 end             otherwise                numstart=str2double(tmpstr(1:IndC-1))-1;                if strcmp(tmpstr(IndC+1:end),'end')                   numend=Ndim;                else                   numend=str2double(tmpstr(IndC+1:end));                end                numcount=numend-numstart;                numstride=1;           end       case {2}           % num0:stride:num1           if IndC(1)==1              numstart=0;           else              numstart=str2double(tmpstr(1:IndC(1)-1))-1;           end           if IndC(2)==IndC(1)+1              numstride=1;           else              numstride=str2double(tmpstr(IndC(1)+1:IndC(2)-1));           end           if IndC(2)==length(tmpstr)                  numend=Ndim-1;           else             if strcmp(tmpstr(IndC(2)+1:end),'end')                numend=Ndim-1;             else                numend=str2double(tmpstr(IndC(2)+1:end))-1;             end           end           numcount=floor((numend-numstart)/numstride)+1;           numend=numstart+(numcount-1)*(numStride);       otherwise           error('Not defined range type')   end end if IsDebug    disp(['tmpstr=',tmpstr])    disp(['start:',num2str(numstart), ' stride:',num2str(numstride),' count:',num2str(numcount)]) end