Opened 6 years ago

Closed 6 years ago

Last modified 6 years ago

#4938 closed defect (invalid)

Low importance given to place=town Lowestoft

Reported by: Pink Duck Owned by: geocoding@…
Priority: minor Milestone:
Component: nominatim Version:
Keywords: Cc:


For the search "Stanford Street, Lowestoft" the result was:

"Stanford Street, Kirkley, Waveney District, Suffolk, East of England, England, NR32 2NZ, United Kingdom"

The expected result is: "Stanford Street, Lowestoft, Waveney District, Suffolk, East of England, England, NR32 2NZ, United Kingdom"

The address features above show that Lowestoft was excluded for having too low an importance, even though the place=town node is just 700 m away. The Waveney district relation won out with 17× the importance.

What causes Lowestoft to be ranked so low? Does something need to change with OSM tagging to resolve this?

Change History (5)

comment:1 Changed 6 years ago by Sarah Hoffmann

Addresses don't take into account importance, it is only computed based on distance and the kind of geometry. Boundary relations always win over place nodes because they are more precise.

You should be able to solve this particular one by adding a town boundary relation for Lowestoft.

comment:2 Changed 6 years ago by Pink Duck

The difficulty is that there's no publicly available definition for the extent of Lowestoft or its suburbs. What could be said though is that the average town has a radius of more than 700 metres, and thus the street in question could be presumed to belong to it.

comment:3 Changed 6 years ago by Pink Duck

In thinking about it, the more specific issue here is that Nominatim returned a place=suburb node in preference to a place=town node, even though place=town was considerably nearer. Towns and suburbs typically work with a town centre area and suburbs situated further out. So if the town node is nearest then the street/address is probably not in a suburb.

As a district area and town node appear to be considered the same level, if a place=town node is nearer than a place=suburb then it would give a better result to pick the town over (or in addition to) the district.

comment:4 Changed 6 years ago by Sarah Hoffmann

Resolution: invalid
Status: newclosed

The place=suburb node had nothing to do with that. Suburbs are on a level below towns, so they are evaluated independently.

I see you've fixed the issue by adding a rough town boundary, so closing this issue.

comment:5 Changed 6 years ago by Pink Duck

While I worked around this particular address, it would be better if Nominatim simply dropped the suburb in preference to the town if the town is nearer for all other cases.

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