[OSM-talk] And the prize for the largest closed way goes to...

Dirk-Lüder Kreie osm-list at deelkar.net
Fri Dec 11 11:00:51 GMT 2009


Anthony schrieb:
> 2009/12/10 Dirk-Lüder Kreie <osm-list at deelkar.net 
> <mailto:osm-list at deelkar.net>>
> 
>     Anthony schrieb:
>      > That does it, I'm making a way with name=Northern Hemisphere.  Or
>     would
>      > that be name=equator.  Doesn't work, does it?
> 
>     No, you can't put in the equator as a *closed* way, since the API
>     doesn't allow the way to wrap around on lon+-180°.
> 
> 
> How does the API determine whether or not a way is closed?  

The "first" node is simply referenced a second time at the "end".

> Isn't it up to the software at the other end of the API to interpret a 
> way which goes from -179 degrees to +179 degrees along the equator?

(JFTR: -180 and +180 degrees are valid longitudes.)

> I assumed (I guess incorrectly), that most software would interpret that 
> as the shortest possible line - a line with a length of 2 degrees, not a 
> line with a length of 358 degrees.

Yes, your assumption was wrong, the software does no wrapping around at 
the 180° Meridian. (currently)

-- 
Dirk-Lüder "Deelkar" Kreie
Bremen - 53.0901°N 8.7868°E





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