The distance between two points was measured with a tape measure or measuring stick. The measured distance was drawn onto mapping paper at a fixed scale. Then, using "area by triangle," the area was calculated.
他表示，測量技術本身其實不難，早期的「圖解法測量」是比較耗時費力，使用平板儀測量，測量兩點距離要拉皮尺或竹尺，再將測量結果以一定比例尺繪於圖紙上，然後在圖上計算面積，不但費時又容易出錯。