After analysis, the map is as follows: (1) The post office is 300 meters east-northeast of the school, and it is 300 ÷100 = 3 (cm) on the map; (2) The library is 400 meters west of the school, that is, 400÷ 100=4 (cm) west of the school. (3) The square is 200 meters northwest of the school, which is 200 ÷100 = 2 (cm) on the map; ′