function diff_modis1b_callback

handles = guidata(gcf);
s = get(gcbo,'Label');
if strcmp(s, 'BT11-BT12')
  x_band = 31;
  y_band = 32;
elseif strcmp(s, 'BT8.6-BT11')
  x_band = 29;
  y_band = 31;
elseif strcmp(s, 'BT11-BT6.7')
  x_band = 31;
  y_band = 27;
elseif strcmp(s, 'BT3.9-BT3.7')
  x_band = 21;
  y_band = 20;
elseif strcmp(s, 'BT11-BT3.7')
  x_band = 31;
  y_band = 20;
elseif strcmp(s, 'BT12-BT4')
  x_band = 32;
  y_band = 23;
elseif strcmp(s, 'BT13.7-BT14')
  x_band = 34;
  y_band = 35;
elseif strcmp(s, 'BT11-BT3.9')
  x_band = 31;
  y_band = 21;
end

var = 'MODIS Level1b';
%if strcmp(handles.modis.select_name, var) == 0 | x_band ~= handles.modis.x_band ...
%         | y_band ~= handles.modis.y_band
  handles.modis.select_name = var;
  handles.modis.select_var = s;
  handles.modis.band = -1;
  handles.modis.x_band = x_band;
  handles.modis.y_band = y_band;
  
  % Read MODIS level1b data
  x_data = read_mod1b(handles.modis.filename.level1b, handles.modis.x_band);
  y_data = read_mod1b(handles.modis.filename.level1b, handles.modis.y_band);
  handles.modis.data = x_data - y_data;

  % Get selected MODIS elements (radiance measurement)
  handles = select_modis(handles);
  handles = plotModisImage(handles);
%end

% Update handles structure
guidata(gcbo, handles);
