A neat new search interface to over 60,000 historic maps launched online earlier this week. Old Maps Online, a joint project between the Great Britain Historical GIS Project at Portsmouth University and Klokan Technologies, operates as an easy-to-use search interface to historical maps from multiple online contributors. Users can search based on modern map locations, because each of the historical maps is overlayed on top of a standard Google Maps API -- based on MapRank Search technology first developed for the Switzerland Kartenportal project. Just search or zoom to your location of interest, and a list of available historical maps that include that area will appear on the right. A timeline slider at the top of the browser allows you to focus your search on a particular time period.
Selecting one of the map results from the right-hand browser brings up a window with additional context, plus a link to the map on the contributor's website. Current contributors include the David Rumsey Map Collection, the British Library, the Moravian Library, the National Library of Scotland, and A Vision of Britain Through Time. Plans are to double the number of maps in the database by the end of 2012, with map collections from the New York Public Library, Harvard University, and other contributors.