public static Transition TransitionProbability(RoadGraph graph, ProjectToRoad projection1, ProjectToRoad projection2, MapMatcherParameters parameters)
{
DirectedRoad road1 = projection1.Road;
DirectedRoad road2 = projection2.Road;
//calculate on road distance
double onRoadDistanceInMeters;
Distance startingDist = projection1.DistanceToEnd;
Distance endDist = projection2.DistanceFromStart;
// Roads are the same:
if (road1.Equals(road2))
{
//negative if going backwards along road
onRoadDistanceInMeters = projection2.DistanceFromStart.DistanceInMeters - projection1.DistanceFromStart.DistanceInMeters;
}
// Road start or end on the same node
else if (road1.End == road2.End || road1.Start == road2.Start)
{
//make this transition impossible
return(Transition.ImpossibleTransition(road1, road2));
}
// Roads are connected (can be same road in opposite direction)
else if (road1.End == road2.Start)
{
onRoadDistanceInMeters = startingDist.DistanceInMeters + endDist.DistanceInMeters;
}
// Try connect roads using Dijstra
else
{
List <DirectedRoad> path;
if (PathFinding.DijstraTryFindPath(graph, road1.End, road2.Start, parameters.DijstraUpperSearchLimit, out path))
{
Distance connectingDist = Distance.Zero;
foreach (var road in path)
{
connectingDist += road.Length;
}
onRoadDistanceInMeters = startingDist.DistanceInMeters + connectingDist.DistanceInMeters + endDist.DistanceInMeters;
}
else
{
//cannot connect up roads. transition probability is zero
return(Transition.ImpossibleTransition(road1, road2));
}
}
Distance haversineDistance = projection1.Coordinate.HaversineDistance(projection2.Coordinate);
return(new Transition(onRoadDistanceInMeters, haversineDistance.DistanceInMeters, road1, road2, parameters));
}
public static Emission EmissionProbability(ProjectToRoad projection, double sigmaValue)
{
return(new Emission(projection, sigmaValue));
}
public Emission(ProjectToRoad projection, double sigmaValue)
{
Probability = ProbabilityFunctions.Gaussian(projection.ProjectedDistance.DistanceInMeters, sigmaValue);
Distance = projection.ProjectedDistance;
}
