The extraction of digital vector data from historic land use maps of Great Britain using image processing techniques

The mapping of the land utilization of Great Britain has taken place periodically for the whole country since the 1930s. This and other subsequent projects produced a series of paper maps, which potentially hold valuable information on land use change across Britain. The Department of Geography at the University of Portsmouth, has been involved with a series of collaborative projects, which have collated and scanned the maps from the First Land Utilisation survey of Great Britain directed by Professor L. Dudley Stamp of the London School of Economics. These maps have been geo-referenced and made available to the public via the Vision of Britain web site (www.visionofbritain.org.uk). Interest was shown by a number of organisations concerning the possibility of extracting vector data from the maps relating to the various land use categories. As part of the research, two pilot projects were carried out at Portsmouth to examine the various techniques available and to ascertain time and costs estimates for the data extraction from the full set of maps. As well as manual digitization, image-processing techniques were used to classify scanned images of the selected maps. GIS software tools were then used to refine and clean the data. This paper reviews the work carried out thus far and highlights some of the problems that have arisen.