Published online by Cambridge University Press: 04 January 2016
Over the past decade or so geographic information systems (GIS) methodology hasbecome an accepted tool in historical research (Gregory and Ell 2007; Knowles2008). Although often regarded as a mapping tool, GIS is perhaps better thoughtof as a type of database. What makes a GIS database unique is that a location isstored for each item of data, with this location taking any of a variety offorms: a point, a line, a polygon representing an area or zone, or, in the caseof a raster system, a pixel. GIS can then present instantly on the screen a mapshowing the distribution of any variable or combination of variables in any ofthe chosen locational formats. This electronic display of information becomes ananalytic tool, allowing the refinement of research questions, with answersdisplayed instantly: GIS creates a display of information once visible only inpaper form, drawn slowly and expensively first by cartographers and then byvector plotters. GIS and its associated tools transform mapping into a dynamicexploratory process.