Ordnance Survey

When I was looking for old maps of the Isle of Man a couple of years ago, I came across a great source of old maps of towns across Britain and Ireland (as well as a couple of the Isle of Man and other places in Europe). I didn't mention them in the post (I perhaps hadn't found them at that point) but I've recently had a bit of an interest in the history of the area around where I'm living, so went back to this supplier to order some old maps of the Elephant and Castle area of London.

Alan Godfrey has been building up an impressive collection of reprints of old Ordnance Survey Maps from the late 19th Century and early 20th Century. The maps, collectively known as The Godfrey Edition, are reproductions of original maps, often scaled down slightly, but printed in extraordinary quality considering the age of the originals.

As described on their website:

Most of the maps are highly detailed, taken from the 1/2500 plans and reprinted at about 14 inches to the mile. They cover towns in great detail, showing individual houses, railway tracks, factories, churches, mills, canals, tramways and even minutiae such as dockside cranes, fountains, signal posts, pathways, sheds, wells, etc.. Each map includes historical notes on the area concerned. Many also include extracts from contemporary directories. The maps are neatly folded, often with an early photograph on the cover. The maps are ideal for local historians, transport historians, and family historians, or simply those with an interest in the town they live in or have visited. The maps are very good value and cost just £2.25 each.

Whenever I've bought maps from them (their whole catalog is online in their map shop) I've found them to be very responsive, with the maps often arriving the next day. Alan Godfrey was also open to the use of names from old maps for the OpenStreetMap project (where they were still relevant, as they often were in Peel in the Isle of Man, where much of the historical street layout still exists).

So, if you're interested in the history of the area around you, I highly recommend these maps as a great start to learning more about how things used to be.

I spent much of my evening today scanning in the 1940 Second War Revision map of the Isle of Man. Now that it's all scanned I took the opportunity to have a closer look around some of the places I'm familiar with back on the Island, as well as some things from the past which I'm not so familiar with.

Much has stayed the same on the Island since this map was made at the start of the Second World War, though there have also been some big changes. Towns have grown in size, bypasses have been built to take increasing traffic out of old centres, train lines that used to run from Douglas through St Johns to Peel and Ramsey have been dismantled, and the airport extended from its wartime status as an aerodrome into something a little bigger.

Before I started looking into the grid system used on this map this evening, I hadn't realised that the maps produced during the war weren't yet using the British National Grid for referencing, and instead were using a military grid that also consisted of 1km grid squares - just not the same ones as the National Grid.

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.

Our visit to the offices of Ordnance Survey in Southampton yesterday was fascinating, with a chance to get an idea for the breadth of stuff they do and learn a little more about some of their work. For those of you who may not know who the OS are, they are the National Mapping Agency for Britain.

The tour of their headquarters started off with an introduction to some of the new research projects they are working on at the moment such as innovative ways of visualising the geographic information they hold about houses, allowing them to be depicted as a 3D object, for example. Next up was a refresher on some of the details of OS MasterMap, the 'definitive digital map of Great Britain', and an overview of some of the potential applications that it could be used for.

After lunch we were taken around a number of departments within the organisation, from cartographic generalisation to their printing services and finally their photogrammetry department.

The guys who showed us the generalisation were basically demonstrating the sort of work they need to do to remove/select/alter clutter such as text from their vast database of geographic information so that they can produce useful 1:10,000 scale maps. They were completing the work that their automated generalisation algorithm started but that requires that human input at present.

The print floor was really interesting to see as we were guided from the order processing stage right through design, making of printing plates, to the actual print presses, guillotines, folding machines and finally to despatch.

The final visit of the day was to see the photogrammetry and aerial photo department who plan the flights that take photos during the summer months and then process all of the information that comes back for inclusion in a number of their products - the most obvious of which is the OS MasterMap Imagery Layer that will provide aerial photo coverage of the whole of Great Britain. They've recently invested in digital technology to simplify the process slightly, and apparently the images returned are of an even higher quality than the optical imagery they are using currently.