R: [postgis-users] match line with road segment

[P.Rizzi Ag.Mobilità Ambiente]

If I undestood it well enough and you are trying to match 
GPS tracked points upon a road system, you should be careful 
about crossings.
Where two roads cross, a GPS point may be nearer to the crossing road
instead of the one the vehicle actually was.
So you should ensure to somehow "stick" to the "correct" road.
Maybe by calculating the azimuth of each individual two-consecutive-points
segment and searching for the road nearest to the ending point 
of the segment _and_ with the azimuth most similar to the segment itself.
Obviuosly sometimes a vehicle actually turns into a crossing road,
so you should also recognize that somehow and _don't_ "stick" in that case...

Bye
Paolo Rizzi


> -----Messaggio originale-----
> Da: postgis-users-bounces at postgis.refractions.net
> [mailto:postgis-users-bounces at postgis.refractions.net]Per conto di
> searchelite
> Inviato: giovedì 17 luglio 2008 16.23
> A: postgis-users at postgis.refractions.net
> Oggetto: RE: [postgis-users] match line with road segment
> 
> 
> 
> 
> 
> Paragon Corporation-2 wrote:
> > 
> > You may be better off snapping the points to the line first 
> before you do
> > a
> > make line.  Take a look at Paul's blog entry.  
> > 
> > 
> > 
> http://blog.cleverelephant.ca/2008/04/snapping-points-in-postgis.html
> > 
> > Sounds similar to what you are trying to do.
> > 
> > Hope that helps,
> > Regina
> > 
> > 
> 
> Thanks for the reply...Yes, I already did that..so, is there 
> any idea what
> should i do next? 
> thanks
> -- 
> View this message in context: 
> http://www.nabble.com/match-line-with-road-segment-tp18479996p
18509643.html
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