[Talk-GB] Places and postcodes -- nodes/areas?

[David Fisher]

On Tue, Sep 11, 2012 at 12:00 PM, Craig Wallace <craigw84 at fastmail.fm>wrote:

> I think most of the postal_code tags on postboxes are just based on the
> ref. eg if the ref on the box is "SE25 29", it is assumed the postbox is in
> the SE25 postcode, so it is tagged as postal_code=SE25.
> Craig


Yes, that's what I think's happened.  People are recording the ref (e.g.
SE25 29) but are also tagged additionally as e.g. "postal_code=SE25".

On 11/09/2012 10:47, Matt Williams wrote:
> I would be surprised if post boxes being labelled with postal codes were
affecting which suburb a certain street is associated with in
> Nominatim.

Sorry, I was unclear.  I don't think this is what's happening; rather,
Nominatim is getting "Thornton Heath" (incorrectly) from somewhere, and
also, separately, "SE25" (incorrectly) from somewhere else.  They're
different instances of the same process.

RE your point about postcodes simply being lists of addresses:  you're
quite right, of course.  People tend to place great importance on living
"within" a certain postcode, and thus we tend to think of them as defining
areas, but they don't really.  I'm happy not to pursue this.  But this
implies that "postal_code=SE25" on a postbox is incorrect -- would you
agree that this is the case, and would you support the removal of such tags?

@Steve Doerr:  Good suggestions -- I have access to both political ward
boundaries and (indirectly) to postcode "boundaries".  However, neither
quite does the job for me.  It's all interesting data though, of course --
and it does provide examples of what different people/organisations think a
certain placename refers to.

@Tom Chance:  Interesting.  In Southwark, wards are tagged as
"boundary=administrative" rather than "boundary=political" -- presumably
this is why Nominatim picks them up?  More generally, I'm glad a long-time
contributor/developer like yourself has given this some thought and
struggled.  You ask "could you decide where Croydon ends and Thornton Heath
begins?" -- well, I could give it a good try... but then what about other,
smaller, suburbs/neighbourhoods like Waddon, Selhurst, Addiscombe -- are
they "part" of Croydon/Thornton Heath or adjacent to it?  (PS Yes, I'd seen
the Dalston page before, and love it :) )   Would you support mappers just
giving it a go, based on a mixture of postcodes/addresses/wards and local
knowledge?

Thanks all, some great responses; always a pleasure.

David.
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