In this article I examine early nautical charts and isolarii, or island books illustrated with maps, for evidence that indicates the maps were made on the basis of first-hand observation by the cartographer. There are very few claims on early nautical charts that the charts were created based on the cartographers’ own observations. I suggest that these claims are rare because chart-making was more an artistic enterprise than as a medium for recording discoveries. This conception of nautical charts changed with the advent of the Age of Discoveries, and claims that charts were made based on eyewitness information become more common. The case with isolarii is very different, although the maps in isolarii derive from the nautical chart tradition. Some of the creators of isolarii claim that their works were based on first-hand experience, but not always truthfully. Other authors neither sailed among the islands they describe nor claim to have visited them.

中文翻译：

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制图师启航：目击者记录和早期现代地图

在这篇文章中，我检查了早期的海图和 isolarii，或带有地图插图的岛屿书籍，以寻找表明这些地图是根据制图师的第一手观察结果制作的证据。很少有人声称早期海图是根据制图师自己的观察创建的。我认为这些说法很少见，因为制图更像是一种艺术事业，而不是记录发现的媒介。随着大航海时代的到来，这种航海图的概念发生了变化，并且声称海图是根据目击者信息制作的说法变得更加普遍。isolarii 的情况非常不同，尽管 isolarii 中的地图源自航海图传统。一些isolarii的创作者声称他们的作品是基于第一手经验，但并不总是如实。其他作者既没有在他们描述的岛屿之间航行，也没有声称曾经访问过这些岛屿。