Also, source code is here: https://github.com/valhalla

Since most routing software is proprietary, I think it would be good to combat it by using a strong copyleft on the Valhalla components. GPLv3+ for client software and AGPLv3+ for server software would be awesome.

glennon

Glancing at the Valhalla repos, it looks like the MIT license across the board: https://github.com/valhalla ; https://github.com/valhalla/thor/blob/master/COPYING ; https://github.com/valhalla/chef-valhalla/blob/master/LICENS... ; etc...

Also, it's not so much that the routing engines are proprietary -- the best ones are not. The underlying databases are the secret sauce.

ma2rten

what are the best ones?

glennon

For speedy street routing, the Open Source Routing Machine: http://project-osrm.org/ Like Google's proprietary routing engine, it leverages the scale of local and regional travel (via contraction hierarchies, arterial travel is suited for precomputed cacheing); result: the system can be tuned to give near instantaneous results. OSRM had been led by Dennis Luxen of Mapbox, though he just moved to Apple. The OP (Mapzen's Valhalla) appears to have a similar approach as OSRM. Good libraries for other scenarios exist; e.g., cycling and multimodal planning -- see: http://wiki.openstreetmap.org/wiki/Routing and OpenTripPlanner https://github.com/opentripplanner/OpenTripPlanner

There's an academic Thesis on the principles of contraction hierarchies that is worth a look if you're in this space. http://algo2.iti.kit.edu/documents/routeplanning/geisberger_... My favorite is actually a Master's thesis that steps through the process of using contraction hierarchies to build a routing engine (MoNav) on OpenStreetMap data. https://code.google.com/p/monav/downloads/detail?name=thesis...

For nuanced or complex problems, set up your objectives and constraints against a good solver: http://en.wikipedia.org/wiki/List_of_optimization_software I'm partial to Google's OR Tools https://github.com/google/or-tools (Apache License).