Wei Te-wen conservatively estimates that there are several thousand maps of Asia made by Europeans. About 40 % of them were done in the 16th and 17th century in European countries for colonialism and trade. Maps from the 19th century done by zoologists, botanists and mining engineers surveying for resources account for another 40 %.
魏德文保守估計說，西方人繪製的亞洲地圖大約有數千幅，其中 16、17 世紀歐洲國家為殖民、為貿易繪製的地圖，約佔 40％；19 世紀西方動植物學家、礦冶工程師探勘資源的地圖，也佔 40 %。