After the recent changes, the search function is playing up again. Things I’m looking for aren’t found, instead places and objects with only tenuous connections to the search term are shown. Try e.g. Bradford Road, Oakenshaw, West Yorkshire (a more than 2 km long street), and what you get is South Bradford Golf Course which is not even on that road. Granted that Oakenshaw is a village that sits astride a boundary of two metropolitan boroughs, but it has worked properly before.
Sorry about that but unfortunately the place and boundary data for the UK in OpenStreetMap is rather unsuitable for creating a geocodable dataset. Figuring out something like “Bradford Road” being in “Oakenshaw” is always going to be a hit and miss until the OSM UK community agrees on some kind of usable standardization.
Indeed, local boundaries are a problem in the UK, in particular as there are a lot of unparished areas, and nobody seems to be able or willing to tell where one village ends and another begins. Still, my impression was that the search involved nearby points associated with place names, which gave mostly sensible (if not always exact) results. However, this does not seem to work as well any more as it used to.
It takes into account boundaries and place nodes. And it makes the assumption that boundaries are hard borders. In this particular case the village place node of Oakenshaw happens to be within the admin boundary of Bradford while Bradford Road happens to be in Kirklees.
Nominatim could work with other kind of area types if admin boundaries as defined by the British government are useless for defining settlements. I’ve considered ceremonial boundaries at some point but they are too sparsely available to be a commonly available solution.
Nominatim might get away with a strategy of using place nodes only in the UK countryside. Sadly results become significantly worse for the big cities.
Totally naive question, and I’m sure there are reasons why it doesn’t already work this way, but could the boundaries be treated as a bit more fuzzy? I.e., check for instances of the searched item within adjacent boundaries too?
It would make processing and searching much more expensive. It would also lead to worse results for a lot of other cases: adjacent settlements tend to have the same street names in many countries, so you don’t want fuzzy there.
Thanks - makes sense.
I was thinking of this in the case where the initial match didn’t return a sensible result (such as this example). That would presumably mitigate the issues you mention but I know edge cases are always a nightmare to deal with and my suggestion would probably have other unintended side effects!
It’s been a while since I checked back last. Anyway, the problem of settlements sitting astride district, county, and even county boundaries does not seem to be specific to the UK.
The trouble is rather that the new(ish) boundaries in the UK often do not agree with any traditional ones, and old local boundaries seem to be mostly ignored nowadays. This may be less of a problem where new civil parishes have been established, but what to do in the so-called unparished areas which can consist of several populated places?
If it is of any help, some old boundaries can be obtained from the topographic maps available at maps.nls.uk - but then, even there one finds multiple types of districts (unitary, sanitary, civil parish, ecclesiastical parish) whose boundaries do not always agree. I can therefore understand why progress may be slow in establishing a boundary database for the UK, but what about using the boundaries of e.g. electoral wards? Better than nothing for sure, even if they change from time to time.
There are numerous hierarchies that could be created for the UK - one is of course the “admin hierarchy” - parish council, who collects the bins, who is responsible for other services, etc. However, this doesn’t really match at all well onto people’s “sense of place” (see this discussion about Northern Ireland, but the same is true about at least England and Wales too).
Another might be based on ceremonial or even traditional counties. The challenge with traditional counties is that I suspect that somewhere like Saddleworth might look more towards Old Trafford rather than Headingley these days, but there are ceremonial counties of Manchester and London. Belfast (as noted in the NI thread) might be a challenge - split between Antrim and Down.
In order to test this theory, I suspect that it “just” needs someone in the UK to set up a test Nominatim instance and feed it ceremonial counties as part of the place hierarchy (perhaps with adjustment to or removal of the admin levels that don’t really match anything any more).
If any ceremonial counties are missing they might need bodging based on data that OSM already has or other data (for a proof of concept they don’t need to be accurate to the individual house).
The tools needed to manipulate data around the size of the UK will run OK on an average PC or relatively low cost cloud server, so cost shouldn’t be a huge blocker for a proof of concept.
The challenge with the UK is that although the information about “people’s sense of place” is mostly available in OSM, it is not uniformly mapped. Sometimes its the administrative boundaries, sometimes ceremonial or traditional ones. I’ve seen historical and parish boundaries fit best. And sometimes, really the place node is the only viable information to go on because the area definition is just too fuzzy. It is difficult to make sense out of this as a non-local, not to speak of coding this into some kind of algorithm.
I’d like to cease the opportunity that SotM-EU is the UK this year, find a few locals to discuss the situation in person and see if we can come up with a suggestion that makes it easier to work with UK data for dumb computers.
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Now officially confirmed, there will be a session at SotM-EU in Dundee on places and boundaries in the UK on Friday, November 14, 4:30 PM. Looking forward to see many of you there in person.
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