[OSRM-talk] Zlevels and Restrictions
woodbri at swoodbridge.com
Thu Nov 28 04:04:10 UTC 2013
I'm read over the documentation again and I am confused by the "Graph
representation" wiki page.
I have a correctly noded graph in pgRouting. By this I mean that all
intersections have a node(s) at them and there are no unnoded intersections.
One of the characteristics of this is the fact that segments at an
overpass/underpass intersection are not really connected because with
zlevel information we have assigned separate nodes for the over pass
node from the underpass node, in spite of the fact that they both have
the same 2D x-y locations (ie: they are separated in Z).
The "Graph representation" page seems to imply that all segments with
shape points are exploded into multiple straight line edges with the
idea that crossing polylines with a common x-y point will become noded.
Is this true? Or am I reading too much into the description? It might be
that this is a reference to how the OSM extraction process behaves,
which seems to validated in the "Processing Flow" page.
More importantly, If I feed OSRM a graph via the normalized file format,
what if any changes are made to my data inside OSRM?
Do I need to create No U-turn restrictions to all my two-way street
segments or are these still created automatically at all nodes on
If I'm generating a normalized formatted file, then I do not have LUA
scripts for the extraction process, but it seems that osrm-routed needs
them to run. I would like to know how to generate these with different
profiles if that is possible so that they match up with the data I put
into the normalized file.
I'm happy to write up or add to existing pages as appropriate if you
provide some guidance to these questions. Sorry I know that this is a
lot to ask but I want to start tackling the turn restrictions and
converting some real data to ORSM rather than the silly grid I was
playing with before.
Dennis, the share memory write up was excellent. Thanks for that!
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