[pgrouting-users] A* vs. Dijkstra and the nature of the A* implementation

Daniel Kastl daniel at georepublic.de
Fri Apr 12 20:16:55 PDT 2013

>  For datasets as large as the one we are working with, this seems to
>> result in a pretty high random IO tax.  I wondered if anyone has some
>> boilerplate modifying the returned route, slicing the nearest ways to
>> the beginning and end points with ST_ClosestPoint or similar?
> I have done this, it is not that hard.
As Steve said, this is not so hard. You can select the closest point on the
nearest road segment and PostGIS has all the function to gibe you a
substring from that point.
There is an example how to do this with Shooting Star, which has some
problems at the moment, but just to get an idea:
Shooting Star routes from road segment to road segment, so the logic is
slightly different. For other algorithms such as TRSP you probably need to
create a temporary node.
So in short, I wouldn't modify the returned route but start from new points.


Georepublic UG & Georepublic Japan
eMail: daniel.kastl at georepublic.de
Web: http://georepublic.de
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