OSMServer/Pathfinding/Pathfinder.cs
2023-04-21 13:43:50 +02:00

206 lines
8.5 KiB
C#

using System.Text.Json;
using OSMDatastructure;
using OSMDatastructure.Graph;
using static OSMDatastructure.Tag;
namespace Pathfinding;
public class Pathfinder
{
public RegionManager regionManager;
public readonly string workingDir;
public PathResult? pathResult;
public Dictionary<OsmNode, double>? gScore;
private Dictionary<OsmNode, OsmNode>? _cameFromDict;
private SpeedType _speedType;
public Pathfinder(string workingDirectory)
{
if (!Path.Exists(workingDirectory))
throw new DirectoryNotFoundException(workingDirectory);
regionManager = new(workingDirectory);
workingDir = workingDirectory;
}
public Pathfinder AStar(Coordinates startCoordinates, Coordinates goalCoordinates,
SpeedType vehicle, double heuristicRoadLevelPriority, double heuristicSameRoadPriority,
double heuristicFewJunctionsPriority, double angleWeightFactor)
{
DateTime startCalc = DateTime.Now;
regionManager = new RegionManager(workingDir);
_speedType = vehicle;
OsmNode? startNode = regionManager.ClosestNodeToCoordinates(startCoordinates, _speedType);
OsmNode? goalNode = regionManager.ClosestNodeToCoordinates(goalCoordinates, _speedType);
if (startNode is null || goalNode is null)
{
pathResult = new(DateTime.Now - startCalc, new List<PathNode>(),0 ,0);
return this;
}
PriorityQueue<OsmNode, double> openSetfScore = new();
openSetfScore.Enqueue(startNode, 0);
gScore = new() { { startNode, 0 } };
_cameFromDict = new();
while (openSetfScore.Count > 0)
{
OsmNode currentNode = openSetfScore.Dequeue();
if (currentNode.Equals(goalNode))
{
TimeSpan calcTime = DateTime.Now - startCalc;
pathResult = GetPath(goalNode, calcTime);
Console.WriteLine($"Path found. {calcTime} PathLength {pathResult.pathNodes.Count} VisitedNodes {gScore.Count} Distance {pathResult.distance} Duration {pathResult.weight}");
return this;
}
foreach (OsmEdge edge in currentNode.edges)
{
OsmNode? neighbor = regionManager.GetNode(edge.neighborId, edge.neighborRegion);
if (neighbor is not null)
{
double tentativeGScore =
gScore[currentNode] + Weight(currentNode, neighbor, edge, angleWeightFactor);
gScore.TryAdd(neighbor, double.MaxValue);
if (tentativeGScore < gScore[neighbor])
{
if(!_cameFromDict.TryAdd(neighbor, currentNode))
_cameFromDict[neighbor] = currentNode;
gScore[neighbor] = tentativeGScore;
double h = Heuristic(currentNode, neighbor, goalNode, edge,
heuristicRoadLevelPriority, heuristicFewJunctionsPriority, heuristicSameRoadPriority, angleWeightFactor);
//Console.WriteLine($"Queue: {openSetfScore.Count:00000} Current Distance: {Utils.DistanceBetween(currentNode, goalNode):000000.00} Visited: {cameFromDict.Count:00000} Current heuristic: {h:00000.00}");
openSetfScore.Enqueue(neighbor, tentativeGScore + h);
}
}
}
}
pathResult = new(DateTime.Now - startCalc, new List<PathNode>(),0 ,0);
return this;
}
private double Weight(OsmNode currentNode, OsmNode neighborNode, OsmEdge edge, double angleWeightFactor)
{
double distance = Utils.DistanceBetween(currentNode, neighborNode);
double speed = regionManager.GetSpeedForEdge(currentNode, edge.wayId, _speedType);
double angle = 1;
if (_cameFromDict!.ContainsKey(currentNode))
{
OsmNode previousNode = _cameFromDict[currentNode];
Vector v1 = new(previousNode, currentNode);
Vector v2 = new(currentNode, neighborNode);
double nodeAngle = v1.Angle(v2);
angle = ((180 - nodeAngle) / 180) * angleWeightFactor;
}
double prio = regionManager.GetPriorityForVehicle(_speedType,edge, currentNode);
return distance / (1 + speed + angle + prio);
}
private double Heuristic(OsmNode currentNode, OsmNode neighborNode, OsmNode goalNode, OsmEdge edge, double roadPriorityFactor, double junctionFactor, double sameRoadFactor, double nodeAngleFactor)
{
double roadPriority = regionManager.GetPriorityForVehicle(_speedType, edge, currentNode) * roadPriorityFactor;
if (roadPriority == 0)
return double.MaxValue;
double speed = regionManager.GetSpeedForEdge(currentNode, edge.wayId, _speedType) * 0.0003;
TagManager curTags = regionManager.GetRegion(currentNode.coordinates)!.tagManager;
TagManager nextTags = regionManager.GetRegion(neighborNode.coordinates)!.tagManager;
bool sameName = false;
string? curName = (string?)curTags.GetTag(edge.wayId, TagType.name);
bool sameRef = false;
string? curRef = (string?)curTags.GetTag(edge.wayId, TagType.tagref);
if(curName is not null)
foreach (OsmEdge pEdge in neighborNode.edges)
{
if ((string?)nextTags.GetTag(pEdge.wayId, TagType.name) == curName)
sameName = true;
if ((string?)nextTags.GetTag(pEdge.wayId, TagType.tagref) == curRef)
sameRef = true;
}
double sameRoadName = (sameRef || sameName ? 1 : 0) * sameRoadFactor;
double junctionCount = (neighborNode.edges.Count > 2 ? 0 : 1) * junctionFactor;
double angle = 0;
if (_cameFromDict!.ContainsKey(currentNode))
{
OsmNode previousNode = _cameFromDict[currentNode];
Vector v1 = new(previousNode, currentNode);
Vector v2 = new(currentNode, neighborNode);
double nodeAngle = v1.Angle(v2);
angle = ((180 - nodeAngle) / 180) * nodeAngleFactor;
}
return Utils.DistanceBetween(neighborNode, goalNode) / (roadPriority + sameRoadName + junctionCount + angle);
}
public void SaveResult(string path)
{
FileStream fs = new (path, FileMode.CreateNew);
JsonSerializer.Serialize(fs, pathResult, JsonSerializerOptions.Default);
fs.Dispose();
Console.WriteLine($"Saved result to {path}");
}
private PathResult GetPath(OsmNode goalNode, TimeSpan calcFinished)
{
List<PathNode> path = new();
OsmNode currentNode = goalNode;
double retDistance = 0;
double weight = 0;
while (_cameFromDict!.ContainsKey(_cameFromDict[currentNode]))
{
OsmEdge? currentEdge = _cameFromDict[currentNode].edges.FirstOrDefault(edge => edge.neighborId == currentNode.nodeId);
HashSet<Tag>? tags =
regionManager.GetRegion(currentNode.coordinates)!.tagManager.GetTagsForWayId(currentEdge!.wayId);
PathNode? newNode = PathNode.FromOsmNode(currentNode, tags);
if(newNode is not null)
path.Add(newNode);
double distance = Utils.DistanceBetween(currentNode, _cameFromDict[currentNode]);
retDistance += distance;
weight += regionManager.GetSpeedForEdge(_cameFromDict[currentNode], currentEdge.wayId, _speedType);
currentNode = _cameFromDict[currentNode];
}
path.Reverse();
return new PathResult(calcFinished, path, retDistance, retDistance / (weight / path.Count));
}
private class Vector
{
public readonly float x, y;
public Vector(float x, float y)
{
this.x = x;
this.y = y;
}
public Vector(OsmNode n1, OsmNode n2)
{
this.x = n1.coordinates.longitude - n2.coordinates.longitude;
this.y = n1.coordinates.latitude - n2.coordinates.latitude;
}
public double Angle(Vector v2)
{
return Angle(this, v2);
}
public static double Angle(Vector v1, Vector v2)
{
double dotProd = v1.x * v2.x + v1.y * v2.y;
double v1L = Math.Sqrt(v1.x * v1.x + v1.y * v1.y);
double v2L = Math.Sqrt(v2.x * v2.x + v2.y * v2.y);
double ang = Math.Acos(dotProd / (v1L * v2L));
double angle = Utils.RadiansToDegrees(ang);
return angle;
}
}
}