Valhalla - A Tiled Hierarchical Open-Source Routing Solution
This talk focuses on the dynamic costing methods applied to Valhalla, open source routing and navigation software built to use OpenStreetMap data. Rather than assigning costs to the routing graph during data import or graph creation, Valhalla performs costing at run time using a wide range of attribution. This allows flexible route generation using the same data. Costing modules exist for automobile, bus, truck, bicycle, pedestrian, and public transit. Each costing method allows for options to differentiate routes - for example bicycle routes have options for bicycle type, willingness to use roads (vs. cycleways and bike lanes), and elevation options to avoid hilly roads.
The talk will also address the way Valhalla "tiles" and creates a hierarchical routing graph using OpenStreetMap data. The tiling of routing data allows more efficient memory management and allows easy download of regional data for off-line, disconnected applications. The ability to perform off-line routing (or "get me back to my route" functionality) has important applications for places where there is limited or no internet connectivity. We hope to demonstrate and discuss a mobile SDK for online route functionality with Valhalla.
Valhalla is an open-source routing project that has been implemented in Mapzen's Turn-by-Turn service.