On 10 September 2012 22:07, David Fisher <[email protected]> wrote: > > I've noticed that in my area (Croydon, S London) a lot of streets & POIs > are identified by Nominatim with a nearby suburb of Croydon (Thornton > Heath) rather than with Croydon town itself. The Nominatim/geocoding guys > said this was due to nodes being used instead of areas, and suggested I > create relations to identify the boundaries of the town and of its > suburb(s). My question is: are there any guidelines on how such > areas/relations should be defined? Political/admin boundaries don't really > help. Is it a case of just using my instinct & local knowledge? Are there > any good examples elsewhere? >
This is a problem across Greater London, and doubtless other cities with a patchwork of suburbs. I've thought about this for years, and never come up with a solution. Nominatim for the area I lived in until recently responds with random things like: "Quorn Road, Champion Hill Estate, South Camberwell ward, London Borough of Southwark, Greater London, London, England, SE22 8RE, United Kingdom<http://www.openstreetmap.org/?minlon=-0.0810027047991753&minlat=51.4621391296387&maxlon=-0.0795270949602127&maxlat=51.4641418457031>" (er, this road is actually though a different estate over the road from Champion Hill Esate) "Lordship Lane, Champion Hill Estate, Camberwell, London Borough of Southwark, Greater London, London, England, SE22 8JG, United Kingdom<http://www.openstreetmap.org/?minlon=-0.0775091052055359&minlat=51.4491157531738&maxlon=-0.0743151977658272&maxlat=51.4555892944336>" (this section is quite a way from Champion Hill Estate, nearest to the East Dulwich place node, and in the East Dulwich ward boundary). "Oakhurst Grove, Peckham Rye ward, London Borough of Southwark, Greater London, London, England, SE22 9QF, United Kingdom<http://www.openstreetmap.org/?minlon=-0.069790706038475&minlat=51.4586029052734&maxlon=-0.0696023926138878&maxlat=51.4608879089355>" (accurate, at least, but residents here would say they live in East Dulwich and people looking for it would be highly unlikely to care what the ward happens to be). It also gets a bit weird with long roads that cross different Nominatim patches. I submitted a report a while back, some of the obvious bugs have been fixed but the wider problem is a shortcoming of data ( https://trac.openstreetmap.org/ticket/4156). I can't see any sensible solution to this, frankly. See this for a humorous attempt to define Dalston: http://thisisntfuckingdalston.co.uk/ It would be a hugely subjective process to try and create boundaries for suburbs of large cities. Could you decide where Croydon ends and Thornton Heath begins? Maybe we should all have a go, map the results so people can debate and refine, and at least be in a better position than the current mess? Google used to be similarly bad, by the way. They seemed to think Camberwell extends across most of Southwark, but recently they've really improved the search results. Regards, Tom -- http://tom.acrewoods.net http://twitter.com/tom_chance
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