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zcw100



Joined: 28/09/2019 15:28:16
Messages: 9
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I'm trying to understand the parentFeature/childrenFatures/nearbyFeatures properties in the rdf dump and I've run across this example that I can't make sense of.

The feature antartica http://sws.geonames.org/6697173/about.rdf lists 8 parentFeatures. The first one is is New Zealand http://sws.geonames.org/2186224/about.rdf

Am I missing something where New Zealand can be a parent feature of Antartica? Argentina is another one.

Are these parent/child features built just from the admin heirarchy or are other features included from the heirarchy table?

While I'm asking I also don't understand how the nearby features are selected or where the dbpedia links are included. Are they the dbpedia/geonames links that dbpedia provides?
marc



Joined: 08/12/2005 07:39:47
Messages: 4196
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yes, they come from the hierarchy table (check the user interace).

the nearby are the top-n closest features from the centroid lat/lng.

The wikipedia links are found in the alternatename table.

Marc

[WWW]
zcw100



Joined: 28/09/2019 15:28:16
Messages: 9
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And n = 9? I would have guessed that it would be 10 but that seems to be the most common count but some have fewer. Is it 10 including the feature you're measuring the distance from and that's why there are a maximum of 9? Is there a maximum distance that would lead some features to have fewer than 9 and if so what is that distance?

marc



Joined: 08/12/2005 07:39:47
Messages: 4196
Offline

yes, the max distance is 10km.

The nearby list is arbitrary. You can anytime build your own nearby lists as you have the coordinates of all features.

Marc

[WWW]
zcw100



Joined: 28/09/2019 15:28:16
Messages: 9
Offline

Sorry, now I'm even more confused. The max distance is 10km from the centroid? So the number of features is unbounded as long as it's withing 10km of the centroid? I can see how it's somewhat arbitrary if the feature is much larger than 10km. Is that what you mean by arbitrary. If it's arbitrary is there some particular reason it's included?
marc



Joined: 08/12/2005 07:39:47
Messages: 4196
Offline

it is included because some users asked for it.
I think it is easier for a user to calculate their own nearby function in exactly the way they need it. The lat/lng is available and to calculate the distance is fairly easy.

Best Regards

Marc

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