Encoding and querying historic map content

Abstract Libraries have large collections of map documents with rich spatio-temporal in-formation encoded in the visual representation of the map. Currently, historic map content is covered by the provided metadata only to a very limited degree, and thus is not avail-able in a machine-readable form. A formal representation would support querying for and reasoning over detailed semantic contents of maps, instead of only map documents. From a historian’s perspective, this would support search for map resources which contain infor-mation that answers very specific questions, such as maps that show the cities of Prussia in 1830, without manually searching through maps. A particular challenge lies in the wealth and ambiguity of map content for queries. In this paper, we propose an approach to de-scribe map contents more explicitly. We suggest ways to formally encode historic map content in an approximate intensional manner which still allows useful queries. We discuss tools for georeferencing and enriching historic map descriptions by external sources, such as DBpedia. We demonstrate the use of this approach by content queries on map examples.