Georeferencing Historical Maps over the Internet

Presentation | Presented

  • Jan Hartmann, University of Amsterdam

Georeferencing historical maps offers some unconventional problems. First, it is often difficult to find reference points in regions where many changes have taken place. Second, maps are often not completely accurate and are seldom based on a global triangulation network, so they have to be rubber-sheeted on the basis of as many control points as possible. Third, the amount of information needed is difficult to organise on standalone desktop GIS systems. Fourth, the prohibitive cost of commercial GIS systems makes deployment of the large number of available volunteers unpractical.
To solve al these problems, an application has been developed in which all data are stored on a central server: a small dedicated Linux cluster. The reference maps are stored as WMS services, the scans as unrectified MapServer maps and the control points in a PostGIS database. Control points are set in regular web-browsers with a javascript-interface (to become available as Open Source), and the final rectification and rubbersheeting takes place with the GDAL utilities.

The Maastricht/Aachen/Liege region (the "Euregio") is one of the most intensely mapped regions of Europe. This fertile, multi-lingual region, far from all political centers, has been the battlefield for all emerging European nation states from 1600 to 1800. Every major war has brought on its plunderings and its maps. The basis for this project are the original cadastral maps from the beginning of the 19th century, which will be georeferenced and vectorised by volunteers. On the basis of this very detailed historical base-map, accurate up to a few meters, all further historical material will be georeferenced. The rectified historical maps will be available via dedicated Internet applications and as WMS services.