On 03/07/2020 11:23, Tony OSM wrote:
I spent part of yesterday navigating the relevant OS and LandRegistry
sites and trying to figure out what we can do.
We can basically put UPRN and USRN into OSM freely - the license is
written to enable that. OS have also separated out the ability to match
UPRN and USRN to address and street records - essentially they are
creating an index into their MasterMap products which are behind a
paywall. So anybody who wants to pay - possibly Logistics companies -
can find exactly where their van has to go, more accurate than a postcode.
It should be relatively straightforward to link USRNs to OSM data, since
the topology will match - most roads don't stack, so where a USRN line
follows the same route as an OSM way that's tagged as a road then they
are the same. Where roads do overlap (eg, the A4/M4 double decker in
West London and various tunnels and flyovers), that should be amenable
to manual resolution. Once a USRN is matched to an OSM named way then
that gives us a name for the USRN that's derived independently of
MasterMap.
You could probably also match the names from OS OpenMap using the same
principle. That doesn't include USRNs, but the LineStrings are likely to
match the Open USRN geometry pretty closely. Either way, it should be
possible to assign names to Open USRNs simply by overlaying them on a
map which already has names.
(I say "relatively" straightforward as the open USRN dataset is supplied
as a Geopackage, so using it requires extracting the data from that.
That's an added layer of irritation, but it's not unsurmountable).
Matching UPRNs to OSM data is likely to be more awkward. In a lot of
cases, of course, it will be simple enough - where there's just one UPRN
assigned to what is obviously a distinct building that's been mapped in
OSM then that UPRN clearly applies to that building. But where there are
multiple UPRNs allocated to a single building then we would need more
data to be able to make the correct links. And that data is probably not
available with a suitable licence.
OS also seem to have been careful not to place UPRN and USRN data into
their other free products so as to make cross referencing difficult.
UPRNs can be linked to adjacent USRNs via the OS Open Linked Identifiers:
https://osdatahub.os.uk/downloads/open/LIDS
That's helpful, because it tells us which part of the road network the
local authority responsible for allocating the UPRNs thinks it's on.
That's not necessarily the same as the street name in the postal
address, but for physical access (which is what matters for things like
deliveries and taxis) it's often more useful than a postal address.
Mark
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