[Talk-us] administrative boundaries and Nominatim
Metcalf, Calvin (DOT)
calvin.metcalf at state.ma.us
Mon Jul 30 19:00:46 BST 2012
So basically if we see nodes like that, get rid of them?
From: Serge Wroclawski [mailto:emacsen at gmail.com]
Sent: Monday, July 30, 2012 12:06 PM
To: Metcalf, Calvin
Cc: talk-us at openstreetmap.org
Subject: Re: [Talk-us] administrative boundaries and Nominatim
On Mon, Jul 30, 2012 at 8:25 AM, Metcalf, Calvin (DOT) <calvin.metcalf at state.ma.us> wrote:
> So I'm somewhat confused about how nominatim actually works. A good
> example is the building I work in (10 park plaza Boston ma) the
> version of nominitum on the website gets the correct location on the
> first try (note mapquest has it as the 3rd result) but they have it as
Often what happens is that you have one of two problems, in this order:
2. Incorrectly prominent areas
Nodes are a major problem. In the case of a node area, Nominatim will attempt to guess at how large/prominent the area is. If it's a city, for example, it will be very lose about how far out it thinks the city borders are. Neighborhoods, same thing, and so you get these odd classifications.
The solution to this is to replace nodes with polygons, period.
Often related is the fact that these nodes are often labeled incorrectly, or the area nearby is. That's why much of Washington, DC is considered part of Fairfax, VA, because Fairfax is a node, and a city.
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