Merge pull request opentripplanner#7482 from leonardehrenfried/traversal-distance

Convert A* walk distance to traversal distance

Author: leonardehrenfried

application/src/main/java/org/opentripplanner/routing/graphfinder/PlaceFinderTraverseVisitor.java

@@ -104,7 +104,7 @@ public void visitEdge(Edge edge) {}
   @Override
   public void visitVertex(State state) {
     Vertex vertex = state.getVertex();
-    double distance = state.getWalkDistance();
+    double distance = state.getTraversalDistanceMeters();
     if (vertex instanceof TransitStopVertex transitVertex) {
       var stop = Objects.requireNonNull(transitService.getRegularStop(transitVertex.getId()));
       handleStop(stop, distance);
@@ -142,7 +142,7 @@ public SkipEdgeStrategy<State, Edge> getSkipEdgeStrategy() {
         }
       }
 
-      return current.getWalkDistance() > furthestDistance;
+      return current.getTraversalDistanceMeters() > furthestDistance;
     };
   }
 

application/src/main/java/org/opentripplanner/routing/graphfinder/StopFinderTraverseVisitor.java

@@ -54,6 +54,6 @@ public List<NearbyStop> stopsFound() {
    * reached.
    */
   public SkipEdgeStrategy<State, Edge> getSkipEdgeStrategy() {
-    return (current, edge) -> current.getWalkDistance() > radiusMeters;
+    return (current, edge) -> current.getTraversalDistanceMeters() > radiusMeters;
   }
 }

application/src/main/java/org/opentripplanner/routing/graphfinder/StreetGraphFinder.java

@@ -107,7 +107,7 @@ private void findClosestUsingStreets(
         .withPreStartHook(OTPRequestTimeoutException::checkForTimeout)
         .withSkipEdgeStrategy(skipEdgeStrategy)
         .withTraverseVisitor(visitor)
-        .withDominanceFunction(new DominanceFunctions.LeastWalk())
+        .withDominanceFunction(new DominanceFunctions.ShortestDistance())
         .withRequest(request)
         .withFrom(linkerContext.findVertices(from))
         .getShortestPathTree();

application/src/main/java/org/opentripplanner/visualizer/GraphVisualizer.java

@@ -1444,7 +1444,7 @@ public void valueChanged(ListSelectionEvent e) {
       stateListModel.addElement("weightdelta:" + st.getWeightDelta());
       stateListModel.addElement("rentingVehicle:" + st.isRentingVehicle());
       stateListModel.addElement("vehicleParked:" + st.isVehicleParked());
-      stateListModel.addElement("walkDistance:" + st.getWalkDistance());
+      stateListModel.addElement("traversalDistance:" + st.getTraversalDistanceMeters());
       stateListModel.addElement("elapsedTime:" + st.getElapsedTimeSeconds());
       outputList.setModel(stateListModel);
 

street/src/main/java/org/opentripplanner/street/model/edge/EscalatorEdge.java

@@ -37,7 +37,7 @@ public State[] traverse(State s0) {
       }
       s1.incrementWeight(s0.getRequest().walk().escalator().reluctance() * time);
       s1.incrementTimeInSeconds((long) time);
-      s1.incrementWalkDistance(getDistanceMeters());
+      s1.incrementTraversalDistanceMeters(getDistanceMeters());
       return s1.makeStateArray();
     } else {
       return State.empty();

street/src/main/java/org/opentripplanner/street/model/edge/StreetEdge.java

@@ -1068,9 +1068,7 @@ private StateEditor doTraverse(State s0, TraverseMode traverseMode, boolean walk
       weight += modeReluctance * request.turnReluctance() * turnDuration;
     }
 
-    if (!traverseMode.isInCar()) {
-      s1.incrementWalkDistance(getDistanceWithElevation());
-    }
+    s1.incrementTraversalDistanceMeters(getDistanceWithElevation());
 
     if (costExtension != null) {
       weight += costExtension.calculateExtraCost(s0, length_mm, traverseMode);

street/src/main/java/org/opentripplanner/street/search/state/State.java

@@ -45,10 +45,8 @@ public class State implements AStarState<State, Edge, Vertex>, Cloneable {
   /* StateData contains data which is unlikely to change as often */
   public StateData stateData;
 
-  // how far have we walked
-  // TODO(flamholz): this is a very confusing name as it actually applies to all non-transit modes.
-  // we should DEFINITELY rename this variable and the associated methods.
-  public double walkDistance;
+  // how far have we traversed through the graph
+  public double traversalDistance_m;
 
   /* CONSTRUCTORS */
 
@@ -75,7 +73,7 @@ public State(Vertex vertex, Instant startTime, StateData stateData, StreetSearch
         .rentalRestrictions()
         .noDropOffNetworks();
     }
-    this.walkDistance = 0;
+    this.traversalDistance_m = 0;
     this.time_ms = startTime.toEpochMilli();
   }
 
@@ -269,8 +267,11 @@ public PropulsionType rentalVehiclePropulsionType() {
     return stateData.rentalVehiclePropulsionType;
   }
 
-  public double getWalkDistance() {
-    return walkDistance;
+  /**
+   * Return how far this state has traversed through the graph, in meters.
+   */
+  public double getTraversalDistanceMeters() {
+    return traversalDistance_m;
   }
 
   public Vertex getVertex() {
@@ -370,7 +371,7 @@ public State reverse() {
 
       editor.incrementTimeInMilliseconds(orig.getAbsTimeDeltaMilliseconds());
       editor.incrementWeight(orig.getWeightDelta());
-      editor.incrementWalkDistance(orig.getWalkDistanceDelta());
+      editor.incrementTraversalDistanceMeters(orig.getTraversalDistanceDeltaMeters());
 
       // propagate the modes through to the reversed edge
       editor.setBackMode(orig.getBackMode());
@@ -516,9 +517,9 @@ private int getAbsTimeDeltaMilliseconds() {
     return Math.abs(getTimeDeltaMilliseconds());
   }
 
-  private double getWalkDistanceDelta() {
+  private double getTraversalDistanceDeltaMeters() {
     if (backState != null) {
-      return Math.abs(this.walkDistance - backState.walkDistance);
+      return Math.abs(this.traversalDistance_m - backState.traversalDistance_m);
     } else {
       return 0.0;
     }

street/src/main/java/org/opentripplanner/street/search/state/StateEditor.java

@@ -195,13 +195,14 @@ public void incrementTimeInSeconds(long seconds) {
     incrementTimeInMilliseconds(1000L * seconds);
   }
 
-  public void incrementWalkDistance(double length) {
+  /**
+   * Increment the distance traversed through the graph in meters.
+   */
+  public void incrementTraversalDistanceMeters(double length) {
     if (length < 0) {
-      LOG.warn("A state's walk distance is being incremented by a negative amount.");
-      defectiveTraversal = true;
-      return;
+      throw new IllegalArgumentException("Traversal distance cannot be negative");
     }
-    child.walkDistance += length;
+    child.traversalDistance_m += length;
   }
 
   /* Basic Setters */

street/src/main/java/org/opentripplanner/street/search/strategy/DominanceFunctions.java

@@ -143,17 +143,13 @@ public boolean betterOrEqual(State a, State b) {
   }
 
   /**
-   * A dominance function that prefers the least walking. This should only be used with walk-only
-   * searches because it does not include any functions of time, and once transit is boarded walk
-   * distance is constant.
-   * <p>
-   * It is used when building stop tree caches for egress from transit stops.
+   * A dominance function that prefers the shortest distance.
    */
-  public static class LeastWalk extends DominanceFunctions {
+  public static class ShortestDistance extends DominanceFunctions {
 
     @Override
     protected boolean betterOrEqual(State a, State b) {
-      return a.getWalkDistance() <= b.getWalkDistance();
+      return a.getTraversalDistanceMeters() <= b.getTraversalDistanceMeters();
     }
   }
 

street/src/test-fixtures/java/org/opentripplanner/street/geometry/TestCoordinates.java

@@ -0,0 +1,18 @@
+package org.opentripplanner.street.geometry;
+
+import org.locationtech.jts.geom.Coordinate;
+
+public class TestCoordinates {
+
+  public static final Coordinate BERLIN_TV_TOWER = of(52.5212, 13.4105);
+  public static final Coordinate BERLIN_BRANDENBURG_GATE = of(52.51627, 13.37770);
+
+  /**
+   * Because it is a frequent mistake to swap x/y and longitude/latitude when
+   * constructing JTS Coordinates, this static factory method makes is clear
+   * which is which.
+   */
+  public static Coordinate of(double latitude, double longitude) {
+    return new Coordinate(longitude, latitude);
+  }
+}