fix(TravelerLocator): Include beginning of routing as start of leg.

src/main/java/org/opentripplanner/middleware/triptracker/TravelerLocator.java

@@ -374,8 +374,7 @@ public static boolean isApproachingEndOfLeg(TravelerPosition travelerPosition) {
      * Is the traveler at the start of a leg.
      */
     public static boolean isAtStartOfLeg(TravelerPosition travelerPosition) {
-        Coordinates legDestination = new Coordinates(travelerPosition.expectedLeg.from);
-        return getDistance(travelerPosition.currentPosition, legDestination) <= TRIP_INSTRUCTION_UPCOMING_RADIUS;
+        return getDistanceToStartOfLeg(travelerPosition) <= TRIP_INSTRUCTION_UPCOMING_RADIUS;
     }
 
     /**
@@ -413,6 +412,33 @@ public static Instant getBusDepartureTime(Leg busLeg) {
         ).toInstant();
     }
 
+    private static double getDistanceToStartOfLeg(TravelerPosition travelerPosition) {
+        return getDistanceToStartOfLeg(travelerPosition, travelerPosition.getLegPositions());
+    }
+
+    /**
+     * Get the distance from the traveler's current position to the leg destination from given leg positions.
+     */
+    public static double getDistanceToStartOfLeg(TravelerPosition travelerPosition, List<Coordinates> legPositions) {
+        Coordinates secondCoordinate = legPositions.get(1);
+        Coordinates firstCoordinate = legPositions.get(0);
+        Coordinates legOrigin = new Coordinates(travelerPosition.expectedLeg.from);
+
+        // HACK:
+        // If the first leg position coordinate is identical to the leg origin,
+        // it probably means the origin is off the street network, so the first shape coordinate is at pos (1).
+        // If the first leg position coordinate differs from the leg origin,
+        // then the origin is probably on the street network, so the first shape coordinate is at pos (0).
+        double distanceToFirstShapeCoords = getDistance(
+            travelerPosition.currentPosition,
+            firstCoordinate.equals(legOrigin) ? secondCoordinate : firstCoordinate
+        );
+
+        double distanceToLegOrigin = getDistance(travelerPosition.currentPosition, legOrigin);
+
+        return Math.min(distanceToFirstShapeCoords, distanceToLegOrigin);
+    }
+
     private static double getDistanceToEndOfLeg(TravelerPosition travelerPosition) {
         return getDistanceToEndOfLeg(travelerPosition, travelerPosition.getLegPositions());
     }

src/test/java/org/opentripplanner/middleware/triptracker/ManageLegTraversalTest.java

@@ -40,7 +40,6 @@
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
-import static org.junit.jupiter.api.Assertions.assertTrue;
 import static org.opentripplanner.middleware.triptracker.ManageLegTraversal.getSecondsToMilliseconds;
 import static org.opentripplanner.middleware.triptracker.ManageLegTraversal.interpolatePoints;
 import static org.opentripplanner.middleware.triptracker.TravelerLocator.getNextWayPoint;
@@ -762,6 +761,30 @@ void cumulativeSegmentTimeMatchesWalkLegDuration() {
         assertEquals(busStopToJusticeCenterItinerary.legs.get(0).duration, cumulative, 0.01f);
     }
 
+    /**
+     * Handles cases where the distance to end of leg was previously incorrectly computed.
+     */
+    @ParameterizedTest
+    @MethodSource("createDistanceToStartOfLegCases")
+    void testGetDistanceToStartOfLeg(Itinerary itinerary, Coordinates coordinates, boolean isWithinRadius) {
+        TrackedJourney trackedJourney = new TrackedJourney();
+        trackedJourney.locations = List.of(
+            new TrackingLocation(Instant.now(), coordinates.lat, coordinates.lon)
+        );
+        TravelerPosition travelerPosition = new TravelerPosition(trackedJourney, itinerary, null);
+
+        assertEquals(isWithinRadius, TravelerLocator.isAtStartOfLeg(travelerPosition));
+    }
+
+    private static Stream<Arguments> createDistanceToStartOfLegCases() {
+        return Stream.of(
+            // Close to start of routing (outside of origin building) for walk trip to One Justice Square
+            Arguments.of( walkGjacTo1js, new Coordinates(33.951786, -83.992887), true),
+            // Inside of origin building away from start of routing for walk trip to One Justice Square
+            Arguments.of(walkGjacTo1js, new Coordinates(33.951563, -83.992954), false)
+        );
+    }
+
     /**
      * Handles cases where the distance to end of leg was previously incorrectly computed.
      */