[Talk-GB] UK Postcode Error Reports

[Gregory Williams]

I think that most of the reduction was due to me going through the obvious formatting issues last weekend. I used an import from the Geofabrik GB extract into an osm2pgsql database looking at the addr:postcode and postal_code tags. The database enabled me to easily get the appropriate OSM object IDs such that I could download and fix each in turn using JOSM after using some judgement.

I've also fixed a few way-off postcodes when compared to the distances to that which OS OpenData CodePoint thought that their centroids were at -- things like postcodes in Edinburgh (EH) mistakenly typed in with an Enfield (EN) postcode -- also identified using my import into PostGIS. Cases which were less clear I've added notes for, to have local mappers review.

Gregory
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On 16 Nov 2016 20:36, at 20:36, "Robert Whittaker (OSM lists)" <robert.whittaker+osm at gmail.com> wrote:
>My daily report of addr:postcode value errors at
>http://robert.mathmos.net/osm/postcodes/osm-errors.html seems to be
>being used by at least one other person, since the numbers of errors
>showing there has dropped significantly now. The page is regenerated
>daily, but unfortunately the data hasn't been refreshed for a few days
>now because the source data on which it relies (The Geofrabrik GB
>extract via the GB Taginfo instance) hasn't been updated in that time.
>
>I've also starting playing with a second report that lists location
>discrepancies of postcode-tagged OSM objects compared with the
>postcode centroid locations in Code-Point Open. This is less of an
>exact science, since postcodes will not all be located at the centroid
>for that postcode unit, and the allowable deviations vary depending on
>the unit. However, you can find an initial list of postcodes that are
>more than 1km from their official centroid at
>http://robert.mathmos.net/osm/postcodes/location-errors.cgi -- there
>are about 1500 of them, although quite a few are in groups where the
>same postcode is on multiple neighbouring objects. Presumably most of
>the 1500 will be cases of a typo being made by an editor or in the
>data source they used, so they'll need manual checking and updating.
>
>If anyone fancies looking at any of these please feel free to dive in.
>If you find any false positives (i.e. errors in the processing, or
>postcodes that genuinely are that far from their centroid), please let
>me know, and I'll see if there's anything that can be improved in the
>tool, or if they need to be marked manually as ok.
>
>Robert.
>
>-- 
>Robert Whittaker
>
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