Posted by Dylan Parry on 11/27/06 14:17

Geoff Berrow wrote:

> So, as a matter of interest, what would you need to do the Auto Trader
> type thing that tells you how far apart two postcodes are. Obviously it
> doesn't need 100 metre precision, accuracy to within a few miles would
> be sufficient.

Basic data, like postcode sectors, would be fine for this sort of thing.
You could probably acquire this simple dataset without going anywhere
near the Post Office data. Several other organisations in the UK compile
data to this sort of accuracy. Then, as Brian said, using the
coordinates, you can pretty much do the maths easily enough. Of course,
if you wanted to factor in the roads etc (ie. distance by road as
opposed to as-the-crow-flies) you would need other datasets, but then
we're getting very expensive.

It gets more complicated if you're using a map projection that is based
on decimal degrees though, because the distance in metres/miles isn't
constant!

However, now we're starting to get into my actual line of business, so
I'll send you an invoice for any further advice <g>

--
Dylan Parry
http://electricfreedom.org | http://webpageworkshop.co.uk

Programming, n: A pastime similar to banging one's head
against a wall, but with fewer opportunities for reward.

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