[Talk-GB] Quarterly Project: Addresses and Postcodes

Philip Barnes phil at trigpoint.me.uk
Thu Oct 19 12:10:03 UTC 2017


The polygons can also overlap. The road I live on is a crescent with different postcodes for odd (outside) and even (inside) resulting in the centroids being close together and within the even area.

Phil (trigpoint) 

On 19 October 2017 13:00:25 BST, Steven Horner <steven at stevenhorner.com> wrote:
>>
>> Postcodes refer to points, not to polygons.
>
>Are you saying a point in OpenStreetMap terms?
>
>UK postcodes generally cover an area/polygon. How big that area is
>appears
>to come down to how much mail that area is likely to receive, I think
>that's how its described on Wikipedia. So it could cover one building,
>a
>street or a huge area if rural.
>
>Ordnance Survey sell CodePoint Polygons which is the polygons each
>postcode
>covers. Obviously we can't use that.
>
>On Thu, Oct 19, 2017 at 12:31 PM, Colin Smale <colin.smale at xs4all.nl>
>wrote:
>
>> In the UK, this algorithm is useless if you expect to get the actual
>> address that you could send a letter to, or that you could ask for
>> directions to.
>>
>>
>>
>> On 2017-10-19 13:23, Marc Gemis wrote:
>>
>> Maybe it is interesting to repeat how Nominatim resolves addresses,
>> just in case someone wants to do a search after adding an address.
>>
>> - Nominatim starts from an address point (or building way with
>> address). It takes the house number from it and the street name.
>> - It tries to match the street name with a nearby street.
>> - The rest of the info, suburb, city, country, etc are taken from the
>> way. i.e. it looks in which boundary the way lies and work its way up
>> the admin levels.
>> - In case there is no boundary, it can use a place node as well to
>> determine the name of a certain admin level, but that is less precise
>>
>> - postal codes are taken from the address point, when specified. This
>> is needed in UK/USA but not in e.g. Belgium or Germany.
>>
>>
>> http://nominatim.openstreetmap.org is your friend to understand where
>> the data is coming from.
>>
>> Of course, if you only work with a relational database (as Lester
>> pointed out), one prefers all data on the address node.
>> Relational DB with GIS extensions do not need this (e.g. Nominatim).
>>
>> Nominatim's approach currently has problems with streets on the
>border
>> of e.g. 2 villages. Sara Hoffmann (Lonvia) told me that there are
>some
>> plans to fix this.
>>
>> regards
>>
>> m.
>>
>> On Thu, Oct 19, 2017 at 10:35 AM, Adam Snape <adam.c.snape at gmail.com>
>> wrote:
>>
>> I'm convinced that many such addresses are unnecessarily long (are
>there
>> really multiple Weldons in the Swanscome postal area?). Nevertheless
>we
>> should have a way of mapping them if they are the official address. I
>agree
>> that more general guidance would aid consistency. My address mapping
>> practice is as follows. I would welcome correction if others feel I
>am
>> doing
>> something incorrectly::
>>
>> The post town
>>
>https://en.wikipedia.org/wiki/List_of_post_towns_in_the_United_Kingdom
>is
>> tagged as addr:city (whether or not it is a city or indeed whether an
>> otherwise more important place is nearer). Though this should all be
>in
>> upper case when used I add the tag in lower case with an initial
>capital
>> letter as it would normally be written in a sentence.
>>
>> For sub divisions of this area the wiki has documented tags
>addr:suburb and
>> addr:hamlet. I tend to default to suburb everywhere except when
>dealing
>> with
>> an actual isolated hamlet. Where there are two subdivisions as in
>Steve's
>> example, I'd use hamlet for the smaller one  and suburb for the
>larger one.
>>
>> The wiki suggests to avoid addr:street and addr:place together but I
>use
>> them for things like named retail/business parks where there is also
>a
>> street address eg. https://www.openstreetmap.org/way/527520264
>>
>> I do not tag the name of the property separately if it is the same as
>the
>> main name=* tag
>>
>> Counties have not been formally part of postal addresses for many
>years.
>> Royal Mail permits people to optionally add the name of the old
>Postal
>> County, modern administrative or ceremonial county, or traditional
>county
>> to
>> their address according to their personal preference, but this plays
>no
>> role
>> in delivery. So I do not tag a county in the address.
>>
>>
>> So I'd tag Steve's example: name=The Spring River, addr:street=Talbot
>Lane,
>> addr:hamlet=Weldon, addr:suburb=Ebbsfleet Valley,
>addr:city=Swanscombe,
>> addr:postcode=DA10 1AZ
>>
>> I hope that helps
>>
>> Adam
>>
>>
>> On 18 Oct 2017 11:49 p.m., "Steve Doerr" <doerr.stephen at gmail.com>
>wrote:
>>
>> On 10/10/2017 19:07, Robert Whittaker (OSM lists) wrote:
>>
>>
>> It doesn't seem to have been mentioned here yet, but this quarter's
>UK
>> mapping project is to improve addresses and postcodes:
>>
>https://osmuk.org/uncategorized/jump-in-to-our-quarterly-mapping-project/
>>
>>
>> It would be useful to have some guidance on tagging for UK addresses.
>For
>> instance, how would you tag the different elements of the following
>address
>> for a pub/carvery that opened recently near me:
>>
>> The Spring River
>> Talbot Lane
>> Weldon
>> Ebbsfleet Valley
>> SWANSCOMBE
>> DA10 1AZ
>>
>> Regards,
>> Steve
>>
>>
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-- 
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