[Talk-GB] Postcode finder based on OSM data

[Matt Williams]

On 17 March 2011 15:53, Jerry Clough : SK53 on OSM <SK53_osm at yahoo.co.uk> wrote:
> Several local authorities (certainly Broxtowe, Gedling and Rushcliffe) round
> here have postcodes on street signs:
> http://www.flickr.com/photos/sk53_osm/5534947666/
>
> I therefore tag the streets with them.

Hmm, now that I think about it, I've seen this too. This is indeed a
valid tagging and one of the few ways we can tag postcodes based on
any on-the-ground evidence and as such it should absolutely not be
ignored.

However, I have seen authorities only put the first part of the
postcode on the sign (e.g. 'CV4') which is not that useful for my
application and is so general there's tools (e.g. codepoint open)
which do a much better job than I.

I'll have to think about how it's best to implement it but at the very
least I think I'll do the following:
- If I come across an associatedStreet relation for which one of the
role=street ways has a postcode tag I'll add it as the postcode on any
of the houses in the relation which don't already have a postcode.
- If there's a clash between any of the data I'll flag it as a 'bug'
in my bug database.

I'm not sure that adding the postcoded street itself to my database
would work since the base unit I work with is the 'house' or 'delivery
point' whereas the street is simply part of the address.

I'm open to suggestions though.

-- 
Matt Williams
http://milliams.com