Book excerpt: Geographic information systems (GIS) can enhance historical research by providing tools to explore the spatial relationships of locations in historical sources. However, no widespread methods currently exist for translating vaguely defined historical spatial information into GIS data formats and producing a location estimate. Other GIS techniques do exist that can model the necessary process. Multi-criteria decision analysis with fuzzy measures can be applied to vague historical records to approximate location. The Wieslander Vegetation Type Map dataset is used to demonstrate the model effectiveness. Results show that this technique successfully translated written descriptions of location into raster, or grid-based, surfaces within a GIS. Given the uncertainty of the qualitative descriptions, the technique resolved the text into a collection of locations instead of a single location, with a probability assigned to each location conveying the ambiguity associated with the results and the probabilistic nature of its interpretation.