Hello Stefan
I mentioned client side generation of GeoJSON from OSM data as an
alternative to a "central GeoJSON API" approach (which API is not
available yet; see below).
As always, it depends on the actual use case. When your application has
its own geo database already, it's probably best to implement the GeoJSON
export there. On the other hand, when you handle only few data from a
source that provides only OSM data (like the main API or Overpass API), it
doesn't really matter where you do the conversion. Or, if you are not
interested in displaying "live" (minutely updated) data, it may be best
not to bother any API on each request at all and do the conversion
beforehand.
That said, the original question for a "central GeoJSON API" is a more
complicated issue, as the conversion from OSM to GeoJSON is not always
trivial. An OSM object can be a LineStrings or a (Multi)Polygon in GeoJSON
depending on context! E.g. one can interpret an administrative boundary as
a border line [LineString] or the containing area [Polygon]. It gets even
more non-trivial for some of the more abstract relation types (turn
restrictions, enforcements, etc.). That said, it may be possible to write
such a GeoJSON API, but it must consider these contexts in some way.
Btw: I think you are mistaken when it comes to Overpass API: it does *not*
return GeoJSON or any GeoJSON like geometry (LineStrings, etc.) [1]. Where
did you see ways as LineStrings as a response from Overpass?
Cheers,
Martin
[1]
http://overpass-turbo.eu/?Q=%3Cosm-script%3E%0A%20%20%3Cunion%3E%0A%20%20%20%20%3Cquery%20type%3D%22way%22%3E%0A%20%20%20%20%20%20%3Chas-kv%20k%3D%22cuisine%22%20v%3D%22pizza%22%2F%3E%0A%20%20%20%20%20%20%3Cbbox-query%20%7B%7Bbbox%7D%7D%2F%3E%0A%20%20%20%20%3C%2Fquery%3E%0A%20%20%20%20%3Crecurse%20type%3D%22way-node%22%2F%3E%0A%20%20%3C%2Funion%3E%0A%20%20%3Cprint%2F%3E%0A%3C%2Fosm-script%3E&C=47.39803;8.61975;18&R
(go to "data" tab)
Am 10.02.2013, 02:06 Uhr, schrieb Stefan Keller <[email protected]>:
To Martin and Ander:
Martin suggested to use Overpass output. He also pointed to
OSM4Leaflet.js which does resolve node id's in ways to linestrings.
I would avoid such client-side calculations (except perhaps it's about
an editor or admin too) since this can be done on server-side.
But I think Overpass can already do that:
[...]
The response includes nodes and ways (which are eal GeoJSON
linestrings) because of the "magic" recurse syntax.
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