Towards the end of the Middle Ages, maps began to be used for sea navigation and other scientific purposes, thus an emphasis on accuracy and angles became common place (Robinson 14). The material experience of the location was erased, while immaterial relationships, such as direction were emphasized. (Harvey 43)
Portolan charts, which appeared around 1270 (Robinson ibid) were sea charts used in navigation. “Few, if any inland features [were] shown” (Harvey 39). Instead, “[a] distinctive feature is the network of so-called rhumb lines that cover the map. At first sight they seem almost arbitrarily drawn but in fact they conform to a careful pattern. Sixteen equidistant points, among them the four cardinal points, would be marked along the circumference of a large notional circle; actual lines then joined (and extended beyond) all these points” (ibid 43). Thus, instead of representing everyday life within these spaces, Portolan charts mapped out spatial relations, foregoing the material to represent only immaterial connections.