[Talk-GB] mapping tunnels

John McKerrell john at mckerrell.net
Fri Sep 28 08:47:20 BST 2007

On 28 Sep 2007, at 00:02, Andy Robinson wrote:

> Thom Shannon wrote:
>> Sent: 27 September 2007 11:19 PM
>> To: talk-gb at openstreetmap.org
>> Subject: [Talk-GB] mapping tunnels
>> Does anyone have any suggestions how to map a long tunnel? I know  
>> how to
>> <snip>
>> Do you think I could figure out some reasonable positions using a  
>> cars
>> odometer and a compass? Or does it not really matter that much?
>> Another option just occurred, the tunnel was started in 1925, so any
>> maps from that era would be out of copyright. Perhaps a trip to the
>> library?
> <snip>
> A trip to the Library may indeed be a sound idea.

Or of course a trip to npemap.org.uk might help:

Though looking at it, it's probably not too much use.

When I mapped Kingsway I basically did a straight line between the  
points where the GPS traces stopped, fortunately the GPS worked  
pretty well even in the cutting, and Kingsway doesn't have any  
junctions. You're probably fine using guesswork really, you should be  
able to do the main straight part quite easily, and then the extra  
exits might be a little flakey, but that's fine until better data is  

I basically had to use a combination of guesswork and looking at the  
aerial imagery when doing the (Liverpool) Northern line between  
Brunswick and Central because it's mainly tunnels and the line wasn't  
built when the NPE maps were made!


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