Extracting digital data from the First Land Utilisation Survey of Great Britain e Methods, issues and potential Brian Baily * , Mark Riley, Paula Aucott, Humphrey Southall University of Portsmouth, Department of Geography, Buckingham Building, Lion terrace, Portsmouth PO1 3HE, United Kingdom Keywords: Land use Historical mapping Cartography Image-processing Vector data Dudley stamp Digital data abstract The First Land Utilisation Survey of Great Britain (LUSGB), coordinated in the 1930s and 1940s by Professor L. Dudley Stamp, is regarded as one of the most pre-eminent surveys of land utilisation in Britain. This paper considers techniques and methodological challenges in converting the wealth of information within the survey into digital vector format. The first steps of this process involve high resolution scanning of the map types of the LUSGB, followed by georeferencing. Supervised classification image processing techniques are then used in order to create a set of signatures from which, following clean up processes, subsequent vectorisation can take place. The paper then explores the resulting digital data from this semi-automated procedure for consistency in order to assess both the proposed method’s accuracy for digitalisation of historic land change, as well as the respective accuracy of each map type of the original LUSGB. In particular, this paper examines the data produced from the one and ten-inch map series and also examines individual colour layer maps produced as part of the printing process. The paper concludes by reflecting on the potential of the semi-automated approach experimented with as well, as the avenues for future research in this area. Ó 2011 Elsevier Ltd. All rights reserved. Introduction Historical land use maps of Great Britain exist for a number of epochs and are potentially invaluable in the analysis of the changing face of the British landscape (Haines-Young & Watkins, 1996). Several authors have explored the applicability of histor- ical data sources to the discussion of land use and landscape change over time (Riley & Watkins, 2006; Swetnam, 2007), changing managements and perceptions of these changes (see Dallimer et al., 2009), and what such sources may tell us in light of contemporary issues such as climate change (Winter, 2009). As Taylor, Walford, and Short (2010, p. 52) have recently noted in this journal, the First Land Utilisation Survey of Great Britain (LUSGB), coordinated in the 1930s and 1940s by Professor L. Dudley Stamp of the London School of Economics, is “regarded as the first and perhaps pre- eminent geographically comprehensive survey of land utilisation in [Britain]”. 1 Taylor et al.’s (2010) paper contributes to the recent interest of historical researchers of applying GIS techniques to capturing from, and offering new understandings, interpretations and analysis of, these sources. 2 Although there has been some critique of historical land use maps, there is also significant evidence that these are rich in detail and may have much to tell us about land use and landscape change (Cousins, 2001; Swetnam, 2007). The LUSGB in particular offers insight into a period of significant agricultural change, what some have termed the beginnings of an ‘agricultural revolution’ (Short, Watkins, & Martin, 2007 , p. 15), and offers a baseline from which subsequent land use change may be charted (Swetnam, 2007). Taylor et al.’s (2010, p. 61) analysis cautions, however, “that establishing a baseline of land use information is not as straightforward as it might at first sight appear”. This can be seen as part of the wider discussion of “shifting baseline syndrome” (Pauly, 1995) whereby criticism is levelled at the tendency of each generation to utilise their own, new, baseline data. A response within this discussion has been a turn towards historians to seek baseline data for the natural world (Nicholls, 2009, p. 2). The following paper, working with the LUSGB, seeks to add to these agendas of converting map data into digital form and the methodological challenges and questions this poses. The collation, scanning, georeferencing and extraction of the vast set of historical data contained within the LUSGB is arguably crucial in order that such material is not lost and in order that it can * Corresponding author. Tel.: þ44 (0)2392848484; fax: þ44 (0)2392842512. E-mail address: brian.baily@port.ac.uk (B. Baily). 1 The survey has also been given recent popular attention in the BBC series Britain from Above, with a discussion of its relevance to the war effort and as a tool for understanding land use change over time (see http://www.bbc.co.uk/ britainfromabove/stories/buildingbritain/dudleystamp.shtml). 2 For useful reviews of the nature of this work, including the different scales of study and technologies employed see Gregory and Healey (2007), Gregory and Ell (2007) and Knowles and Hillier (2008). Contents lists available at ScienceDirect Applied Geography journal homepage: www.elsevier.com/locate/apgeog 0143-6228/$ e see front matter Ó 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.apgeog.2010.12.007 Applied Geography 31 (2011) 959e968