function mark_delays(scan_file, range, markerstyle, markersize, color_map, bar_location)

scan = load(scan_file);
data_sizes = size(scan.delay_values);

%color_map = load('blue_map.ddt');
%color_map = cool(128);
%color_map = autumn(140);
%color_map = color_map(1:128,:);
map_size = size(color_map,1);

for y_index = 1:size(scan.y_ticks,2)
    for x_index = 1:size(scan.x_ticks,2)   
        value = scan.delay_values(y_index,x_index);
        fill_flag = 1;
        if value < range(1)
            color = color_map(1,:);
            fill_flag = 0;
         elseif value > range(2)
            color = color_map(map_size,:);
         else
            c_index = round(map_size*(value-range(1))/(range(2)-range(1)));
            if c_index <= 0
               color = color_map(1,:);
            else
               color = color_map(c_index,:);
            end
         end
         x = scan.x_ticks(x_index);
         y = scan.y_ticks(y_index);
         if fill_flag == 1
            plot(x, y, markerstyle, 'Color',color,'MarkerFaceColor',color,'MarkerSize',markersize);
         else
            plot(x, y, markerstyle, 'Color','k', 'MarkerSize',markersize);
         end
    end
end

% now draw a colorbar if required:
if nargin > 5
    x_range = get(gca,'XLim');
    y_range = get(gca,'Ylim');

    if strcmp(bar_location,'bottom') 
        height = (y_range(2)-y_range(1))/20;
        width = (x_range(2)-x_range(1))/map_size;
        for c_index = 1:map_size
            color = color_map(c_index,:);
            rectangle('Position',[x_range(1)+(c_index-1)*width y_range(2)-height width height], 'FaceColor',color,'EdgeColor',color);  
        end
        text(x_range(1)-markersize*3, y_range(2)+markersize*2, num2str(range(1)), 'FontSize',markersize);
        text(x_range(2)+markersize, y_range(2)+markersize*2, num2str(range(2)), 'FontSize',markersize);
    elseif strcmp(bar_location,'right')
        height = (y_range(2)-y_range(1))/map_size;
        width = (x_range(2)-x_range(1))/20;
        for c_index = 1:map_size
            color = color_map(c_index,:);
            rectangle('Position',[x_range(2)-width y_range(2)-c_index*height width height], 'FaceColor',color,'EdgeColor',color);
        end
        text(x_range(2)+markersize, y_range(1), num2str(range(2)), 'FontSize',markersize*2);
        text(x_range(2)+markersize, y_range(2), num2str(range(1)), 'FontSize',markersize*2);    
        
        line([x_range(2)-width ; x_range(2)], [(y_range(1)+y_range(2))/2 ; (y_range(1)+y_range(2))/2],'Color','k');
        text(x_range(2)+markersize, (y_range(1)+y_range(2))/2, num2str((range(1)+range(2))/2), 'FontSize',markersize*2);
    elseif strcmp(bar_location,'top')
        height = (y_range(2)-y_range(1))/20;
        width = (x_range(2)-x_range(1))/map_size;
        for c_index = 1:map_size
            color = color_map(c_index,:);
            rectangle('Position',[x_range(1)+(c_index-1)*width y_range(1) width height], 'FaceColor',color,'EdgeColor',color);  
        end
        text(x_range(1)-markersize, y_range(1)-markersize*2, num2str(range(1)), 'FontSize',markersize);
        text(x_range(2)-markersize, y_range(1)-markersize*2, num2str(range(2)), 'FontSize',markersize);
    else
        disp(['sorry, ''' bar_location ''' option is not supported']); 
        beep
    end
end