[GraphHopper] Storing additional node properties

[Andreas Wolf]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA256

Hi,

I need to store information about some nodes (pillar and tower) in the
graph. More specifically, I’m interested in traffic lights and some
traffic signs.
I don’t need to have this used during routing, as I will only use the
route calculated by Graphhopper as a base for further calculations –
so as long as it is not totally off limits, it is good enough for my
purpose, even if the travel times are sometimes much too low. But
probably we can improve that with my work…

My first approach, based on the work by Jan Soelter, was to store the
count of traffic lights for each edge, using two flags for traffic
lights at the start and end of the edge, plus a counter for the
intermediate traffic lights.
This works in general, but has several flaws. One is that it is
impossible to get the exact location of the light, which would be a
problem on longer roads (imagine a pedestrian crossing on longer roads
within a city).
I also did not find a way to get the direction of travel, which makes
the start/end flags kind of not-so-useful.

My current idea is to store the additional data with the nodes, which
would remove the above mentioned flaws and would enable me to get a
detailed list of road segments with the traffic signs and lights along
them. That is basically what I need in the end.

My only problem now is that I did not find a way to store node
properties without a custom storage extension.
Is there a kind of "node flags" like there is for edges and I just
overlooked it?
Or is a storage extension (which would make using turn costs
impossible) the only viable solution? If yes, would it be an option to
integrate node flags into the graph storage?


Regards
Andreas
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v2

iF4EAREIAAYFAlVVwl8ACgkQRJlqDhrZfp2TkQEAgIs/9BoH1nG0z3ss/paZlSaU
Iqi4ytVYBcmCFDwGktEBAMBs/wrl+JluBsn5a/UWgLLOAPAL679TVZ4YAejn74Le
=zzua
-----END PGP SIGNATURE-----