Georeferencer Project: Crowdsourcing location data for historic maps
In 2011 the British Library set up the Georeferencer project to crowdsource the georeferencing of its collections of scanned historic maps. By adding georeference (coordinate) data to the old maps, they can be viewed alongside modern maps via the Old Maps Online data portal and the catalog of georeferenced maps.
Using illustrations extracted from digital books and public domain images posted on Flickr, many of the maps were identified and geo-tagged by a team of volunteers as part of a Maps Tag-a-thon event that ran from Nov 2014 to January this year. Among the collections of maps released so far are the Ordnance Surveyors’ Drawings (one inch to a mile maps for England and Wales 1780 – 1840) and the Amercian Civil War collection.
To date, over 8000 maps have been successfully georeferenced and quality checked by a panel of reviewers.