Walking in a fixed direction is more complicated than it sounds. First you must fix your position. To do so, visually impaired persons must use all of their non-visual senses to read clues to fix their position relative to their surroundings.
所謂定向行動，首先必需先定位，視障朋友必需利用各種感覺器官，配合各種線索，找出自己與環境的關係。