Map Matching (Pillow) Nodes Missing in MatchResult

karussell · May 30, 2018, 7:47am

We are doing a minor “douglas peucker” point reduction on import:

graphhopper/graphhopper/blob/master/reader-osm/src/main/java/com/graphhopper/reader/osm/OSMReader.java#L735


        // Too large is very rare and often the wrong tagging. See #435 
        // so we can avoid the complexity of splitting the way for now (new towernodes would be required, splitting up geometry etc)
        LOGGER.warn("Bug in OSM or GraphHopper. Too big tower node distance " + towerNodeDistance + " reset to large value, osm way " + wayOsmId);
        towerNodeDistance = maxDistance;
    }


    EdgeIteratorState iter = graph.edge(fromIndex, toIndex).setDistance(towerNodeDistance).setFlags(flags);


    if (nodes > 2) {
        if (doSimplify)
            simplifyAlgo.simplify(pillarNodes);


        iter.setWayGeometry(pillarNodes);
    }
    storeOsmWayID(iter.getEdge(), wayOsmId);
    return iter;
}


/**
 * Stores only osmWayIds which are required for relations
 */

You could disable that via providing a custom OSMReader.

And if you are using the web service (I guess you are not) we do a second simplification step to reduce the geometry overhead: https://github.com/graphhopper/graphhopper/blob/master/core/src/main/java/com/graphhopper/GraphHopper.java#L229