[Talk-GB] Import UK postcode data?
davefoxfac63 at btinternet.com
Fri Oct 4 12:47:03 UTC 2019
On 04/10/2019 01:52, ndrw6 at redhazel.co.uk wrote:
> On 04/10/2019 00:26, Dave F via Talk-GB wrote:
>> I think you're missing the point. Most contributors believe postcodes
>> on buildings or property nodes, add quality to the OSM's database,
>> but object to the import of codepoint as it's just not accurate
>> enough as stated in this, & numerous other threads.
> This is incorrect. CPO/ONSPD postcodes _are_ accurate, up to date and
> include all postcodes in the UK except NI.
Please note: "not accurate *enough*"
> They are not complete (contain one and only one delivery point per
No. The centre point is not associated with *any* delivery point. It is
an arbitrary mean, calculated mathematically. it could, in theory, be
located in the middle of a park.
Even postcodes unique to one property/business aren't accurate as their
positions are misaligned by the effect of adjacent areas.
> which is pity, but that's not a reason not to use the ones that are
> available, which is still _far_ more that what we have in the database.
Quantity does not equate to quality.
> This may not be a perfect solution but the information CPO/ONSPD
> contains is still extremely useful for geocoding. Search for a
> postcode and you are _guaranteed_ to get an address in a close
> vicinity to a place you are looking for.
No. With an import of the centroids points you're only guaranteed to be
given the location of the node with the postcode.
> How about not needing to start Google Maps when searching for a
> location on the go?
>> There's no point in importing to stand alone nodes as deliveries are
>> destined for buildings. Adding to streets is also pointless for the
>> same reason plus they can have multiple postcodes.
> Addresses on nodes are commonly used in the UK OSM. Many mappers
> prefer them over placing addresses on buildings. There are also many
> cases (POIs) where nodes are objectively better than buildings. So,
> no, there right and wrong solution here.
Allow me to clarify. I should have maybe said 'properties' which can be
represented by nodes instead of 'buildings'.
My objection, which I thought was clear, was to "standalone nodes" with
just a postcode tag.
> Besides, the main reason for importing these data is that we can get
> _all_ postcodes in the database.
Again quantity /= quality. If you can't manipulate data then it's
useless. These standalone postcode nodes will relate to nothing.
> This gives users confidence that when they search for a postcode they
> will reliably get a result they are looking for. This is not possible
> when merging postcodes with buildings simply because we still have
> only a small fraction of buildings in the database.
> By the way, I'm not against merging addr:postcode with buildings,
> that's exactly what I was doing myself when adding postcodes manually.
> However, this is not a process that can be automated (lack of
> buildings, single OSM buildings having more than one address/postcode).
Then add buildings.
> Based on my experience with mapping postcodes with CPO, I would
> recommend starting with an import and merge postcodes and buildings
Experience has shown that doesn't happen. I'm thinking US TIGER imports,
but I'm sure there are other examples.
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