[MATLAB] read the byte-binary ice concentration data from NSIDC

function myice=readgsfcice(fname,fnamemask) % read the binary ice concentration data from gsfc % similar to the fortran version here % data description: %     http://nsidc.org/data/docs/daac/nsidc0051_gsfc_seaice.gd.html % data : %     ftp://sidads.colorado.edu/pub/DATASETS/nsidc0051_gsfc_nasateam_seaice/final-gsfc/north/ % mask : %     ftp://sidads.colorado.edu/pub/DATASETS/brightness-temperatures/polar-stereo/tools/masks/ % usage: %     myice=readgsfcice(ice_filename, mask_filename) %     myice: ranging 0 to 1, land value is nan if the mask file is specified %     http://scriptdemo.blogspot.com   isMask=1; if nargin<1    help readgsfcice    return elseif nargin==2    if ~exist(fnamemask,'file')       disp(['mask file not found: ',fnamemask])       isMask=0;    end end if nargin==1    isMask=0; end if ~exist(fname,'file')    error(['file not found: ',fname]) end % read the data fid=fopen(fname,'r'); % read the header myheader=(char(fread(fid,300,'uchar')))'; nrow=str2num(myheader(13:18)); ncol=str2num(myheader(7:12)); myscale=str2num(myheader(121:126)); %read data block myice=fread(fid,'uint8'); fclose(fid); % read the mask file if isMask==1    fid=fopen(fnamemask,'r');    mymask=fread(fid,'uint8');    fclose(fid);    myice(mymask==1)=nan; end myice=reshape(myice,ncol,nrow)/myscale;