We have written an article which has been published in the July edition of Applied Geography about some of the techniques we have used in analysing the first Land Utilisation Survey maps from the 1930s.
Baily, B., Riley, M., Aucott, P. and Southall, H. (2011) ‘Extracting digital data from the First Land Utilisation Survey of Great Britain – methods, issues and potential.’ Applied Geography, Volume 3, Issue 3, pp959-968
http://www.elsevier.com/wps/find/journaldescription.cws_home/30390/description#description
I liked your article is an interesting technology