Searches for cartographic materials have previously been carried out using conventional library search systems. However, this kind of search method often proves to be inadequate, as the lack of suitable user interfaces means that queries have to be formulated in words. Furthermore, indexing based on geographical names does not adequately describe the spatial dimension of cartographic material, and geographical names also tend to be ambiguous and inclined to change. A web-based geographical search system (geosearch), which analyzes the geographical coordinates of MARC21 field 034, has been developed for the Swiss research portal for maps. The geosearch enables cartographic material to be found quickly and efficiently on the basis of its location and spatial extent via an intuitively accessible user interface. This is achieved with a cleverly devised ranking algorithm (MapRank^®) and an innovative indexing mechanism. The number of search results can also be restricted by applying filters relating to the publication period and map scale.
The geosearch is proving to be a powerful search tool which, in an open-ended search scenario, can be used to find roughly double the amount of relevant cartographic material within a short space of time. The system is intuitive to operate and no previous knowledge is required. It also offers further strengths, such as the ability to search through extremely large quantities of data quickly and independently from the various subject heading systems and thesauri. This makes the geosearch an ideal tool for carrying out map searches in metacatalogs.