Dennis Lee Bieber wrote: > On Sun, 14 Oct 2012 18:11:50 +0100, Ian Goddard<goddai01@hotmail.co.uk> > declaimed the following in soc.genealogy.computing: > > >> I'm in the UK. But a 1st edition 6" map is the best part of a century >> older than the current coordinate system. The maps use Cassini rather >> than Mercator (and, according to information received, have different >> meridians for different counties). This means that either the old maps >> have to be used as is with an arbitrary set of coordinates which are >> simply pixel coordinates or reprojected onto OSGB. >> > Ouch: > http://www.ordnancesurvey.co.uk/oswebsite/freefun/geofacts/geo1164.html Ouch indeed. Although this reference implies that there may only be two meridians to contend with a recent email from OS customer service suggests more. Forty more. -- Ian The Hotmail address is my spam-bin. Real mail address is iang at austonley org uk