Find your way with openstreetmap.la

I'm really happy to announce the latest update on openstreetmap.la: Routing has been integrated to the main page.

As illustrated in a previous post I evaluated the capabilities of the Open Source Routing Machine amongst other routing engines. The speed and the web-oriented architecture of the Open Source Routing Machine convinced me to use it as a backend to implement routing on openstreetmap.la.

Open Source Routing Machine: Yet another routing engine

Initially I only wanted to some routing on OpenStreetMap data with GRASS GIS. Then I also tried pgRouting and later SpatiaLite. Using pgRouting as backend, I set up a simple web application following the well explained pgRouting workshop. But I wasn't really satisfied since the routing starts only at the closest node, that's basically less a problem in the city than on the countryside with less junctions (and thus less nodes).

Finally I turned away from GIS to specialized routing software for OpenStreetMap, namely to Routino and to the Open Source Routing Machine, short OSRM. I was that impressed by the speed of OSRM, that I decided to have a deeper look at this engine:

Pros

• Speed! OSRM is about speed and it claims to be capable to handle continental sized networks using memory efficient third party libraries like google-sparsehash. It was a matter of seconds to preprocess the 6.2 MB Laos PBF file.
• Web-oriented: includes a server that runs on a configurable port and thus it is very easy to integrate in any web application.
• Since it's developed for OpenStreetMap, it considers out of the box OpenStreetMap tags like oneways etc.

Cons

• Configuration is not trivial, since speed and highway categories are hard-coded.
• Installation with Scons was very laborious on the server, since I had some dependencies in my home directory and it was necessary to fiddle the SConstruct file.
• Missing GeoJSON support. But since it needs anyway a proxy script to use OSRM in Ajax requests, it was a quick hack to reformat the homebrew JSON output to proper GeoJSON.

I adapted the simple web frontend I developed for pgRouting to work with OSRM as backend and put everything online. I'm pleased to present the current proof-of-concept prototype:

http://www.openstreetmap.la/dev/routing/

As soon as time allows I'll integrate the routing on the openstreetmap.la main page.