Suitability Paramaeter not explained

Dchemist · November 25, 2019, 6:28pm

Hello All!

I just started working on a project and I need to use ORS data for this research. However I have nolticed that , much was written about the suitability parameter. Nor is how it is derived explained. I would appreciate any help on the the suitability value for a route is derived. Thank you

adam · November 26, 2019, 8:19am

Hi @Dchemist,
suitability is a bit of a tricky one to explain as there are a lot of factors that affect it depending on the profile that is being requested. For the driving profiles, the suitability is based on the speed of the road, where the slower the road speed, the lower the suitability. For profiles where speed isn’t as important (i.e. pedestrian) then the suitability is based on a number of properties relating to the way itself. For example, with the pedestrian profiles things that increase suitability include the class of road (small residential street vs a sidewalk on a main road), presence of sidewalks on higher speed roads, and if the way contains things like tunnels.

You are right though, the documentation should be updated to include some more information about what suitability is, so I will pass this along to those in charge of that.

Dchemist · December 14, 2019, 9:11pm

Thank you Adam for this reply. However I suspect that the suitability parameter might contain just the algorithm i need for my thesis but i have to first understand whats its based upon. The profile of interest is cycling - regular. Can you point out a code or part of a code or algorithm that evaluates suitability values for this profile. That would really help, thank you once more.

adam · December 17, 2019, 2:44pm

I think the bit of the code that does it for bikes is at

github.com

GIScience/openrouteservice/blob/e3a09219b805fc56991355dbab1ce51ce326060f/openrouteservice/src/main/java/heigit/ors/routing/graphhopper/extensions/flagencoders/bike/CommonBikeFlagEncoder.java#L696


            return AVOID_AT_ALL_COSTS;
        default:
            return UNCHANGED;
    }
}


/**
 * @param weightToPrioMap associate a weight with every priority. This sorted map allows
 *                        subclasses to 'insert' more important priorities as well as overwrite determined priorities.
 */
void collect(ReaderWay way, double wayTypeSpeed, TreeMap<Double, Integer> weightToPrioMap) {
    String service = way.getTag("service");
    String highway = way.getTag("highway");
    // MARQ24 MOD START
    if(!isRoadBikeEncoder){
    // MARQ24 MOD END
        // MARQ24 MOD START
        //if (way.hasTag("bicycle", "designated") || way.hasTag("bicycle", "official")) {
        if (way.hasTag("bicycle", "designated") || way.hasTag("bicycle", "official") || way.hasTag("bicycle_road", "yes")) {
        // MARQ24 MOD END
            if ("path".equals(highway)) {

or at least that is the bit that collects the different properties and changes the priority of the way based on them, though be warned that it is likely that other places also affect which things make the way more suitable.

Also, the code has been edited quite a bit in the latest release which will make its way into the master branch soon, so in a few weeks the code will look different