Upper and lower panels show the relative (referred to the “center of motion”) and absolute (corrected for the apparent motion, see Sect. 2) proper motions of the 6.7 GHz methanol masers, respectively. Colored vectors indicate the direction and the amplitude of the proper motions. The black vector in the bottom right corner of the panels indicates the amplitude scale of proper motions in kilometer per second. Dotted vectors are used for the most uncertain proper motions. Colors, symbols, the gray-scale map, the white big dots, the dotted rectangles, the S-shape dashed polygon, and the dotted ellipse, have the same meaning as in Fig. 1.