A couple of weeks ago I started looking around on eBay for old maps of the Isle of Man, partly because they may be of some use to the OpenStreetMap project, and partly because it would be really interesting to see what had changed in the past fifty or hundred years around the Island.
The thing that triggered me to go out and find them was the launch of Richard Fairhurst's online browser of the 1930s and 40s Ordnance Survey New Public Edition map of England and Wales. He'd spent quite some time collecting the maps from secondhand shops knowing that 50 years after their publication the copyright on them expired and hence they get released into the Public Domain where anybody can do with the data what they wish. He worked with a couple of other people to scan all of the maps and build a site that lets people browse them and start to build up a copyright-free database of postcodes. It lowers the barriers for people willing to share the locations of their postcodes, and makes it much easier (though less accurate) than the Free The Postcode method of getting people with GPS units to submit precise coordinates for postcodes they know.
But back to the maps of the Island. The one map I was most interested in was the Second War Revision (Sheet 17) published by the Ordnance Survey in 1940. It covers the Isle of Man at a similar scale as the modern Sheet 95 of the Landranger series, but is now in the public domain, having been published 66 years ago under Crown Copyright. It will be a great reference point for extracting data for OpenStreetMap, showing the paths of rivers and roads between towns and villages on the Island. It doesn't really give enough detail to be useful within the towns themselves.
I also found some old street plans of Douglas, Onchan, Ramsey, Port Erin, Port St Mary and Castletown dating back to the late 40s (the Peel plan appears to state Nov 47). They can't be used for anything other than personal interest, as far as I'm aware, because they weren't published under Crown Copyright and the copyright instead falls either under the local authorities of those places, with the cartographers, or with the publisher. All of which mean that the maps won't fall out of copyright until at least 70 years after they were published, or 2017. Or at least, that's as I understand it.
The 1963 Ordnance Survey map (Sheet 87) I also found would have fallen out of copyright a little before that, in 2013, but in reality it probably doesn't give much more information than the 1940 version, and the Island will have long been mapped in OpenStreetMap by that point.
Talking of mapping the Isle of Man, I am planning to do some more mapping of Castletown and Douglas for OpenStreetMap between Christmas and New Year. If anybody is interested in helping out or finding out more, just get in touch. I have a spare GPS unit that can be used as well.