THOR engine for OsmAnd

[Norbert]

OsmAnd needs a new routing engine because of bad performance. Graphhopper and OSRM do not fulfill the requirements because they don't support conditional edge-weights at query-time*. THis is necessary to support options like avoid highways and so on without the need for a separate CH-graph for each combination of options.

Competitor maps.me suffers from a similar problem**. The use fast OSRM engine but can't offer routing options (avoid highways etc.).

It should be investigated if THOR*** engine (Tiled Hierarchical Open Routing) which supports multi-modal routing can be implemented in OsmAnd to replace the current routing engine.



* https://github.com/Project-OSRM/osrm-backend/issues/2377
** https://github.com/mapsme/omim/issues/1888
*** https://github.com/valhalla/thor
*** https://mapzen.com/blog/valhalla-intro/

[Harry van der Wolf]

THOR might be a good alternative, but the A* algorithm OsmAnd uses is just fine.

I agree that OSRM is too limited due to its inflexibility.

It is the implementation of the A* algorithm in OsmAnd that is wrong (from my point of view). OsmAnd is literally the only app that uses a heuristic coefficient of 1.0 thereby increasing both memory usage and calculation time extremely. And it sometimes even calculates the wrong route (due to over-optimization?).

I use a heuristic coefficient of 1.25 or 1.3 which makes the calculation 3-4x as fast!! and I can calculate routes up to 2000 km (less memory usage) where I could calculate up to 800 km (1.5GB memory in my phone) . And routes were never worse and in some cases even better: faster and shorter!

With that configured the route calculation is still not the fastest but completely acceptable.

There is only one disadvantage: deviating from the default 1.0 in OsmAnd makes that blocked roads (by users themselves for whatever reason) are no longer recognised. I assume that is an omission in OsmAnd. I can't consider it a bug as Victor developed OsmAnd for that hc=1.0 (but I still I think it is a bug :)  as other A* algorithms apps have no problem with that).

Next to that: OsmAnd knows speed penalties for traffic lights, speed bumps and the like. It seems that THOR supports that too (dynamic run-time costing) but is not yet implemented, but maybe I'm wrong.

The other reason for me for not using OsmAnd for car navigation is the slow rendering of the screen.

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[Jack Burke]

Not trying to hijack this thread, but Harry, where exactly in routing.xml do you change the heuristicCoefficient value?  I see 2 possible places:

At the beginning, there's this section, with the value unset:

<osmand_routing_config defaultProfile="car">
	<!-- 1. parameters of routing and different tweaks Influence on A* : -->
	<!-- f(x) + heuristicCoefficient*g(X) -->
	<!-- TEMPORARY needs to be reverted to 1 -->
	<attribute name="heuristicCoefficient" value="" />

Then just a little below that is this section, with a value of 1.5 commented out:

<routingProfile name="car" baseProfile="car" restrictionsAware="true" minDefaultSpeed="45.0" maxDefaultSpeed="130.0" leftTurn="5" rightTurn="5" roundaboutTurn="5" onewayAware="true"> <!-- <attribute name="heuristicCoefficient" value="1.5" /> --> Are you supplying a value for the 1st, or uncommenting and using the 2nd? --jack

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[Harry van der Wolf]

I add the value to the first (but that's not really necessary) and I set the car profile itself, like

<routingProfile name="car" baseProfile="car" restrictionsAware="true" minDefaultSpeed="45.0" maxDefaultSpeed="130.0" leftTurn="5" rightTurn="5" roundaboutTurn="5" onewayAware="true" heuristicCoefficient="1.25">

I don't touch the outcommented value

Make sure that OsmAnd has really been closed otherwise the new value will not be used. It will then use the already loaded in-memory value.

Rebooting the phone is obviously the most simple way.

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[Jack Burke]

Thanks!

[Norbert]

I have file an issue on the OsmAnd bug tracker in order to reach the developers:
https://github.com/osmandapp/Osmand/issues/3201