The geometry I have found and corroborated was mostly done on Ordnance Survey maps, the 1:25,000 series especially.  This programme is the story of these maps and their accuracy.  Wonderful programme, and I am much indebted :http://bbc.in/1gaihq1  OK you may have to copy the link and paste in a search thingy, the link ain't live for some reason!? - 20/2/17 ach, the prog not available now!