Historical GIS

Historical GIS brings the spatial-analytic power of geographic information systems to the study of the past, building databases in which historical places, boundaries, and phenomena are tied to coordinates and to the dates at which they held. Systematized in Ian Gregory and Paul Ell's foundational treatment, the approach addresses a problem ordinary GIS ignores: the geography of the past was not fixed. Administrative units split and merged, borders shifted, towns rose and vanished, so a historical GIS must represent geometry that changes through time. Researchers georeference old maps, digitize past boundaries, encode places in gazetteers, and link tabular historical data, censuses, tax rolls, trade figures, to these time-varying geographies. The result supports genuinely spatial questions: how phenomena were distributed, how patterns clustered or diffused, how distance and terrain shaped historical life. It operationalizes the Annales attention to geography as a force in history, letting scholars map and measure the spatial structures within which past societies acted.