Crowdsourcing the past – georeferencing website puts historic maps in their place

The British Library is calling on members of the public to help in a digital quest to reveal the hidden context of historic maps.

800 items have been selected for the Georeferencer Project from the British Library’s collection of over 4.5 million maps. The georeferencing interface enables people to plot locations on historic maps by comparing a digitised image with present-day online maps.

By choosing points that correspond between the historic map and the present, the user generates an overlay in Google Earth allowing us to see how areas have changed and developed over time giving a modern day context for maps up to 400 years old.

The last time the British Library undertook such a project the response from the public was remarkable, with 708 maps completed in less than one week. Volunteers who take part in this georeferencing project will have their name attached to each tag so they will be able to chart their progress and see what they have contributed to the overall project. When the project is completed the most prolific georeferencer will be announced by the British Library.

“This project brings together people’s passion for maps and history with the latest online crowdsourcing tools,” says Kimberly Kowal, Lead Curator of Digital Mapping at the British Library. “Although many locations have changed significantly over the centuries, sometimes almost beyond recognition, only a handful of common features – street intersections, buildings or some natural features – are necessary to link the past with the present."

“It’s easy to use and highly addictive – and a fascinating way to explore the past while improving the information that underpins our digitised collections,” she adds.

The results will be made available online, allowing people to see historic locations across the world viewed alongside the satellite-enabled mapping of the 21st century.

This is the third time the British Library has called for online volunteers to assist with geolocating its vast map collection but never before has the project gone global. The 800 maps stretch around the globe, with examples from every continent and cover from the seventeenth to the twentieth centuries. Most of the maps in the project were made for British use and so give an interesting visual account of the activities of Britain on a global scale. The project encompasses maps which were made for a variety of uses ranging from military and topographic maps, surveys of natural resources, and port and town plans from across the world.

As a result of these previous successful rounds of public crowdsourcing, those maps are now spatially enabled, allowing users to search and navigate maps online. Maps from previous rounds are accessible through the Library’s Old Maps Online portal, a JISC-funded effort containing online historic maps from some of the best map collections worldwide. It is hoped that people will be as responsive on this occasion allowing both the British Library and the public to discover how the world around us has developed.

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The British Library is the national library of the United Kingdom and one of the world's greatest research libraries. It provides world class information services to the academic, business, research and scientific communities and offers unparalleled access to the world's largest and most comprehensive research collection. The Library's collection has developed over 250 years and exceeds 150 million separate items representing every age of written civilisation and includes books, journals, manuscripts, maps, stamps, music, patents, photographs, newspapers and sound recordings in all written and spoken languages. Up to 10 million people visit the British Library website - www.bl.uk - every year where they can view up to 4 million digitised collection items and over 40 million pages.  

The British Library’s collection of Cartographic and Topographic Materials is the national map library of Great Britain, with a collection of nearly 4½ million atlases, maps, globes and books on cartography, dating from the fifteenth century to the present day. This makes the collection the second largest in the world (after the Library of Congress). The Library receives through copyright deposit the complete range of British production. It also acquires foreign topographical maps at medium and small scales, supplemented by regular deposits of superseded mapping from the Directorate of Military Survey, as well as thematic and general atlases and maps. The historical collections are added to steadily through purchase and donation. www.bl.uk/maps/


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