[OSM-talk] New Popular Edition maps, and postcode collection

[Richard Fairhurst]

On 24 Oct 2006, at 09:13, Dominic Hargreaves wrote:

> On Tue, Oct 24, 2006 at 03:09:49AM +0200, lars wrote:
>
>> Great work!  But the map doesn't come out quite as detailed as I
>> had hoped and it looks a little unsharp.  In particular the
>> sharpness seems to vary with folds and bends in the map, e.g.
>> http://www.npemap.org.uk/tiles/map.html#323,206,1
>> http://www.npemap.org.uk/tiles/map.html#495,123,1
>>
>> What technology did you use to digitize the map?  Did you document
>> the process?
>
> I expect that Richard can explain how the scans were produced.

(Sorry for late reply - been on holiday.)

Nothing too technical, I'm afraid. Step one was to spend lots of time  
(and some money) collecting the sheets. (It's quite an interesting  
bit of social history: the south-western sheets, such as Bude and  
Paignton, could be picked up anywhere for pennies; the Midlands were  
reasonably easy to find; the northern sheets were much, much harder  
to locate. Says a lot about holiday habits in the forties and fifties.)

I'd estimate this took a couple of years, on and off. I could have  
done it more quickly had I been prepared to spend money with  
specialist OS map dealers such as David Archer, but because the maps  
could be obtained much more cheaply (if erratically) elsewhere I  
didn't feel I needed to.

Step two was to find a scanning bureau that didn't charge the earth.  
Scanning them myself simply wasn't an option because of the size of  
the sheets. I eventually settled on Preview Services, based near  
Heathrow, who do a lot of work for local authorities scanning old  
architects' diagrams. They seemed to kind of enjoy having a different  
challenge for once.

Step three was to buy a new hard drive to store them on - the full- 
resolution scans fill five DVDs! Total cost for the lot was just over  
£1000.

I guess the biggest lesson I learnt from it all was that unfolded  
paper maps are orders of magnitude better to scan than anything else.  
Most of the NPE scans are either folded paper or (sometimes) folded  
cloth. I'm now starting all over again with the OS Seventh Edition  
(the one after the NPE), but this time not buying anything apart from  
unfolded paper maps.

Right now, though, I'm ridiculously impressed by the cool stuff that  
people have started to do with the scans. Really makes it all  
worthwhile, and full credit to the other "Charlbury-based code  
ninjas" (thanks Steve :) ) for building the npemap site.

cheers
Richard