Historical geographic information system
A historical geographic information system (also written as historical GIS or HGIS) is a geographic information system that may display, store and analyze data of past geographies and track changes in time. It can be regarded as a subfield of historical geography and geographic information science.
GIS was originally developed for use in environmental sciences, military and for computer assisted cartography. The tools developed for these uses are ill suited for the features of historical data.
Techniques used in HGIS
- Digitization and georeferencing of historical maps. Old maps may contain valuable information about the past. By adding coordinates to such maps, they may be added as a feature layer to modern GIS data. This facilitates comparison of different map layers showing the geography at different times. The maps may be further enhanced by techniques such as rubbersheeting, which spatially warps the data to fit with more accurate modern maps.
- Reconstruction of past boundaries. By creating polygons of former administrative sub-divisions and borders, aggregate statistics can be compared through time.
- Georeferencing of historical microdata (such as census or parish records). This enables the use of spatial analysis to historical data.
Notable Historical GIS projects
- Great Britain Historical GIS, A GIS enabled database holding diverse geo-referenced maps, statistics, gazetteers and travel writing, especially for the period 1801-2001 covered by British censuses. Public access via the Vision of Britain site. Created and maintained by Portsmouth University.
- China Historical GIS similar project for Imperial China developed by the universities of Harvard and Fudan, China.
- David Rumsey Historical Map Collection, one of the world's largest map collections, which has digitized and georeferenced a large part of its collection and published it on the internet.
- Electronic Cultural Atlas Initiative (ECAI) a clearinghouse for the exchange of metadata of Historical GIS. Maintained by the University of California, Berkeley.
- HGIS Germany Institute of European History (Mainz) and Institute i3mainz at the University of Applied Sciences 
- Belgian Historical GIS tracks the development of administrative boundaries in Belgium since 1800. Developed by the University of Ghent
- The National Historical Geographic Information System (NHGIS) system for displaying and analyzing Census tracts and tract changes in the United States.
- HistoAtlas is an open historical geographical information system that tries to build a free historical atlas of the world.
Software or web services developed for Historical GIS
- TimeMap — A Java open-source applet (or program) for browsing spatial-temporal data and ECAI data sets Developed by the department of archaeology University of Sydney.
- Version 4+ of Google Earth added a time line feature that enables simple temporal browsing of spatial data
- Ian N. Gregory, Paul Ell: Historical GIS: Technologies, Methodologies, and Scholarship (Cambridge Studies in Historical Geography) 2008 ISBN: 978-0521671705
- Anne Kelly Knowles: Past Time, Past Place: GIS for history A collection of twelve case studies on the use of GIS in historical research and education. ESRI press 2002 ISBN 1589480325
- Anne Kelly Knowles, Amy Hillier eds.: Placing History: How Maps, Spatial Data, and GIS Are Changing Historical Scholarship 2008 ISBN 978-1589480131
- Ian N. Gregory: A place in History A short introduction to HGIS by the lead developers of GBHGIS ISSN 1463-5194
- Ott, T. and Swiaczny, F.: Time-integrative GIS. Management and analysis of spatio-temporal data, 2001 Berlin / Heidelberg / New York: Springer ISBN 3540410163
- Feature edition of Historical GIS in the journal Social Science History 24 2000, Introduction by Anne Kelly Knowles.
- HGIS Germany (in German)
- Web site for the Belgian Historical GIS
- Project homepage
- Announcement of the featureat the Google Earth blog