gc.foreground = pixmap.get_colormap().alloc_color( colorname )
dest_x , dest_y = self.gps2pix( coords , ( center_x , center_y ) )
gc.foreground = pixmap.get_colormap().alloc_color( colorname )
dest_x , dest_y = self.gps2pix( coords , ( center_x , center_y ) )