You may also not be aware of Geolytix set of postcode areas/districts & sectors which is built from the ONS data and other OS OpenData sets: https://www.geolytix.co.uk/ look in Geodata menu.
You also have to process the centroids to remove very noisy data (RM Delivery centres, some local govt offices, some businesses) where many postcodes share a centroid. Also be aware of oddities such as NG80 & NG90 (& formerly I think L99) for businesses with high mail volumes (Boots, Experian & the Liverpool pools companies). There are algorithms to assign postcodes to roads which work for roads with only one postcode or two postcodes for evens/odds. This would have been a lot easier if the Land Registry Prices Paid data did not turn out to be tainted. 3 datasets which do help are Companies House, FHRS & National Register of Social Housing, but I'd be surprised if this covered more than 30% of postcodes in E&W. Obviously many centroids can be assigned provisionally to a road just by using st_shortestline, but quite a lot of iteration is required to deal with the errors. Once assigned to roads buffers can be used to approximate geometries, but more work & iteration to then tessellate the country. Always the fly-in-the-ointment is that a postcode is not a true polygon but a collection of delivery points, so it's actually fairly meaningless to place a road lacking any addresses with a given postcode. Jerry On 5 December 2016 at 20:32, Chris Hill <o...@raggedred.net> wrote: > On 05/12/16 20:19, Dave Barter wrote: > >> Excuse the noob question as I’ve not been on the list long. >> >> I’m doing a bit of work trying to create an open version of the OS >> Codepoint Polygons. To do this I need as much postcode data as possible. >> I’ve been looking at extracting this from OSM and as far as I can tell I’m >> looking for the following tags:- >> >> -addr:postal_code >> -addr:postcode >> -postal_code >> -postcode >> >> Are there any others I’m missing? And I guess I am (sadly) right in >> thinking there is not a huge amount of data in there, circa 40-50k records? >> >> Thanks >> Dave >> >> > Have you looked at the OS Opendata Codepoint? They are centroids, not > polygons. You can see an overlay on OSM on my map here: > > http://oscompare.raggedred.net/?zoom=15&lat=53.73731&lon=-0. > 48844&layers=BFFTFF I have a simple overlay, that the map uses, too. More > details here: http://codepoint.raggedred.net/ > > There are Office of National Statistics postcode files too under Open Gov > licence. They have the same active postcode centroids as Codepoint but with > extra detail for each postcode and expired postcodes too. > > -- > Cheers, Chris (chillly) > > > _______________________________________________ > Talk-GB mailing list > Talk-GB@openstreetmap.org > https://lists.openstreetmap.org/listinfo/talk-gb >
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