The world mapped as a supply chain
Zhao Rugua, a Quanzhou customs official who never went abroad, built his picture of foreign lands from interviews with visiting merchants and from earlier written sources. Each country is described mainly by what it produces, what it buys, and how its ships reach China, so geography is organized around trade flows. This shows how an administrator's position shapes what counts as knowledge: the world becomes an inventory of tradeable goods and the routes that deliver them.