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.
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.
DaveF
On 03/10/2019 01:40, nd...@redhazel.co.uk wrote:
On 02/10/2019 13:43, Russ Phillips via Talk-GB wrote:
I'm wondering if it would be feasible and advisable to import the UK
postcode data from OS OpenData Codepoint
<https://wiki.openstreetmap.org/wiki/Ordnance_Survey_OpenData#Code-Point_Open>.
I support it. From my own experience, requests like this tend to
attract objections, so it is important for people who agree with such
proposals to speak out.
The key and, in my opinion, sufficient reasons for importing postcodes:
- Objectively, postcodes are an important type of addressing and
geocoding data in the UK. We've had two quarterly projects encouraging
adding postcodes to the OSM database. Some people (including myself)
don't like the fact the postcodes are proprietary to Royal Mail but we
are here to map the world, not to judge it.
- They are accepted in the OSM database and there is no tagging
ambiguity. Their place is _in_ the OSM database, not in external
overlays. They are searchable in most applications (OsmAnd, Maps.me),
the exception is Nominatim, which uses an outdated overlay but this is
more a workaround for lack of such data in the database, than a solution.
- Code-Point Open is a legal and open source of postcode data. In fact
it is the _only_ legal source of such data in bulk. All other sources
are either derived from CPO or are based on local knowledge.
All reasons _against_ the import I've seen so far are based on
personal preferences. People are objecting because they don't like the
idea of proprietary address data, do not find them important enough,
do not find them comprehensive enough. These views are useful in
establishing the context but are not a reason to block the import of
what _is_ available.
Talking about technical aspects:
- The key (and deliberate) limitation Code-Point Open is that it
doesn't distinguish between residential postcodes and postcodes
assigned to "large users". This is not ideal but still useful - we
know the postcode exists at a given location, we just can't be sure if
it is the only postcode there.
- Quality of building in OSM database. Large buildings, especially in
town centres, are often not partitioned correctly. Different parts may
have different street names and postcodes. Code-Point Open may in fact
be helpful in finding and correcting such issues.
- Some postcodes are for PO boxes (usually collocated with post
offices) are are best left out.
My recommendation: import missing postcodes "as is" (as points) with
extra tags denoting the import, import date and an accuracy metric
from CPO. Keep it searchable and easy to remove or update, if
necessary. Code-Point Open is updated quarterly and sometimes
centroids move to another building. Filter out PO boxes and postcodes
which are already in OSM (I usually check if there is an OSM object
with a matching addr:postcode within a 10m radius of the code point).
Do not attempt to merge them with buildings as it is not guaranteed to
work in all cases. This is best done manually and in some cases it may
require a survey.
Best regards,
ndrw6
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