Well, I've done enough maps processing on my own, so it's time to see if somebody else can help. Basically, I want to recalibrate all the 1923 MOT Half Inch maps as there are numerous errors, particularly around the coast which just don't look right - the aim then is to be able to trace vector routes from them as mentioned in this thread.

This is mildly technical - you don't need to be a programmer to do it.

Go to http://www.sabre-roads.org.uk/temp/transfer/mot and you'll see a bunch of map images, and a file maprect.zip. Download MapRect, unzip it and run it. Download a map image, click on "Open" and open it.

Now, start at the top left hand corner and click on every grid line intersection, going from left to right, top to bottom. As you click, each pixel gets annotated in the list to the left and marked with a red blob so you can see it. If you make a mistake, click on "Undo" to remove the most recently added marker.

When you've finished, you should end up with something like this.



Now save the file and attach it to this thread.

Each one should probably take half an hour the first time you do it (though I've got it down to about 15 - 20 minutes). I've attached a few I've done already for you to see how it's done.

Any questions, let me know.

Windows only?

Yes, and it doesn't even work on mono for some reason, which means I have to dig out an ancient laptop just to run it (my main boxes are Mac OS and Debian). I knocked up the app a few weeks ago in an hour or two after work - didn't have time to do anything else. I do plan to port it to wxWidgets if I have time and there's enough interest.

I'm having try now.

I take it I need to click on the borders as well from your example?

Can I save and come back to it later?

Every time I run it I get 'MapRect.exe has stopped working' (on Windows 7, both with and without compatibility mode).

Yes, you need to do the corners, the T sections for the borders and grid squares, and the grid squares themselves.

Johnny, I think you need to run MapRect.exe in the same directory as sabre48.ico - I can't remember why I did it like that, and if I could remember where I put the source, I'd fix it.

Is this what you had in mind, Ritchie?

Here's an attempt at it. Not precise, but it's lined up pretty damn well in my eyes.

The process may be "only mildly technical"; however, I am far too much of a computer ignoramus to work out how (properly) to get from

Instruction A) Download MapRect, unzip it and run it.

to

Instruction B) Download a map image, click on "Open" and open it.

The first two times I only succeeded in disconnecting myself from Sabre. The third time I did succeed in loading a map image (through copying its web address: probably totally the wrong thing to do!) but, alas, got only part of the way through performing the calibration when I got disconnected from the internet altogether, which was fairly alarming...

That could have been just co-incidence, though given my level of expertise in computing matters it's more likely to be something I did!

Am going to be away for a few days, but am very willing to give it another go when I get back; however, I do need a little more hand-holding about how to get from A) to B)!

Steven - that's excellent, exactly what I was after
Lenzar - your one has got a couple of rogue pixels, but I think I can sort that out
Swarkestonecauseway - you can't reload earlier work (the left hand box is free form text where you can put in anything) but it would be nice to do
Viator - just download a map image and open it locally, the calibration doesn't do anything over the network.

Thanks for helping out so far everyone - I'll have a look at your work when the queue on my tiling server has died down a bit

So I clicked all the intersections (finished one) went to press save and there was nothing in the file type box, but I pressed save anyway assuming something magical and computery was going to happen, tried to upload it and it said the extension wasn't allowed.

Should I be saving as CSV? and how do I do that?

I just type "MOTx.csv" and click on "Save".

Had a bit of a spree Wednesday and yesterday evening, and I've done all of England and Wales except 33, 37, 38 and 39 (plus 2 and 16 which you lot did).

I'll try 33 then if no-one else is doing so?

Here's 33.

I had a bit of trouble in that I missed one out, so I copied all the ones from the missing coordinate down, inserted the missing one, and pasted the rest back in, so I hope it still works OK. I also hope it's accurate enough.

Excellent - many thanks.

Sheet 37 is done now.

Thanks to everyone who helped with the calibration. The tiles are being processed as I write this and in the process of being uploaded. Things may appear wonky for a few hours, but everything should be up by this evening.

Among some highlights : the join between the English and Scottish sheets (which use a completely and utterly different projection system) is better, Cornwall and Pembrokeshire aren't completely wonky, the A625 around Mam Tor hasn't got a big hole in it (unlike the real life version!), joins along the south coast are better, the Isle of Thanet isn't squashed anymore (I await a humorous jape relating to that comment) and route traces are generally more accurate - certainly enough to show you what's changed since 1923 and what hasn't.

Thanks again.