why reference matrix is shown as empty matrix when I am reading a geo tiff file from matlab 2010a?

I imported modis images(reprojected to geographic coordinate system) in matlab 2010.But, reference matrix is shown as empty one and I cant find geographic coordinate of interesting points. Plz can you explain where I was wrong and give a solution for me. Thanks.

Answer 1

[Chad Greene]

I'm guessing your MODIS image is a plain tiff and not a geotiff. Sometimes there's a supporting text file that may have information about the coordinates of the image corners. Sometimes those corner coordinates are called the G-Ring or G-Polygon and you have to build the georeferencing matrix from that information. The landsat function tackles the same problem like this:

% Find G-polygon text in metadata file: 
latind = regexp(txt,'G-Ring_Latitude');
lonind = regexp(txt,'G-Ring_Longitude');

% Get values of polygon vertices: 
for k = 1:4
    lats(k) = str2double(txt(latind(k)+17:latind(k)+27));
    lons(k) = str2double(txt(lonind(k)+17:lonind(k)+27));
end

% Create georasterref:
R = georasterref('LatLim',[min(lats) max(lats)],...
    'LonLim', [min(lons) max(lons)], ...
    'RasterSize', size(I),'ColumnsStartFrom','north');

[tharaka suranjan]

Thank you very much Chad. I wish u all the best dear friend.