He also tells the reader, when assessing an old map, how it is necessary to take into account the speed and course of the initial explorers to explain how the mapmaker could turn mountains into islands; why sandbars, coral reefs, and islands that we know today ended up depicted as landmasses; or why certain landmasses were drawn so excessively large.
他也教導讀者，在拿到一張古地圖時，如何根據最初航行者的速度、航向等變數，解釋製圖者為什麼會將山頭畫成島嶼，為什麼今天的淺灘、珊瑚礁和島嶼，在當年地圖中卻是一大片土地，以及為何有些陸地會被畫成特別的大。