[Talk-us] Towns as Areas or Points

Emilie Laffray emilie.laffray at gmail.com
Tue Aug 31 11:44:20 BST 2010

On 31 August 2010 11:36, Serge Wroclawski <emacsen at gmail.com> wrote:

> As so often happens in OSM, a small mystery turns into a big question,
> so here's mine for the week:
> If you don't want the explanation, just skip down to the part where it
> says "THE QUESTION".
> I live in a place called Silver Spring, Maryland.
> It's not prominently displayed on the map: http://osm.org/go/ZZcfj5yN-
> Yet Takoma Park, which is much smaller, does.
> It turns out the reason is that the node for this town is:
> http://nominatim.openstreetmap.org/details.php?place_id=437409
> And has the tag hamlet.  Silver Spring is not a hamlet. It has about
> 80,000 people living in it according to
> http://en.wikipedia.org/wiki/Silver_Spring,_Maryland
> My initial thought was "Well we should change the point", but then I
> discovered this relation:
> http://www.openstreetmap.org/browse/relation/133501
> Which seems better (it still says that SS is a locality, which is
> essentially the same as a hamlet/village, but it at least has the
> administrative boundaries).
> Do I fix the node? Do I copy the tags from the node into this relation
> and then fix the relation?
> Why was the node the thing that came up in nominatim searches, and not
> the relation?
> If I remove this node, will bad things happen?

In theory, nothing wrong will happen if you delete the point. The place
value should be probably changed in both cases. In terms of rendering,
Mapnik will create a center of gravity point for the polygon. Essentially
you will end up with two names displayed on the map.
In France, we keep the two systems, a point and a relation for marking a
town. The main reason is that the point can be used to reflect what the
proper center of the town is.
I don't think Nominatim rates locality very high compared to an hamlet. I
can tell you that at work, we are ignoring place=locality for our reverse

Emilie Laffray
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