[trails] Use half way waypoints

tests/trails_tests/test_gpx_importer.py

@@ -9,6 +9,7 @@ from django.core.files import File
 from locations.models import GeoLocation
 from scrobbles.importers.trail_gpx import (
     compute_trail_stats,
+    find_route_waypoint,
     import_trail_gpx,
     parse_trackpoints,
 )
@@ -182,6 +183,24 @@ class TestTrailGPXImportModel:
         assert imp.processed_finished is not None
 
 
+class TestFindRouteWaypoint:
+    def test_returns_halfway_point(self, sample_gpx_path):
+        result = parse_trackpoints(sample_gpx_path)
+        pt = find_route_waypoint(result["points"])
+        assert pt is not None
+        lat, lon = pt
+        assert lat == pytest.approx(34.177853, abs=0.001)
+        assert lon == pytest.approx(-118.829944, abs=0.001)
+
+    def test_returns_last_point_for_short_track(self):
+        points = [(34.0, -118.0, None, None), (34.001, -118.001, None, None)]
+        pt = find_route_waypoint(points)
+        assert pt == (34.001, -118.001)
+
+    def test_returns_none_for_empty_points(self):
+        assert find_route_waypoint([]) is None
+
+
 class TestFindByTrailhead:
     def test_exact_match(self, db):
         geo = GeoLocation.objects.create(lat=34.190598, lon=-118.844015)
@@ -206,6 +225,49 @@ class TestFindByTrailhead:
         found = Trail.find_by_trailhead(34.190598, -118.844015)
         assert found is None
 
+    def test_same_trailhead_same_route_matches(self, db):
+        geo = GeoLocation.objects.create(lat=34.190598, lon=-118.844015)
+        trail = Trail.objects.create(
+            title="Same Route Trail",
+            trailhead_location=geo,
+            route_lat=34.192167,
+            route_lon=-118.843143,
+        )
+        found = Trail.find_by_trailhead(
+            34.190598, -118.844015,
+            route_lat=34.192167, route_lon=-118.843143,
+            tolerance_m=100,
+        )
+        assert found == trail
+
+    def test_same_trailhead_different_route_does_not_match(self, db):
+        geo = GeoLocation.objects.create(lat=34.190598, lon=-118.844015)
+        Trail.objects.create(
+            title="Different Route Trail",
+            trailhead_location=geo,
+            route_lat=34.200000,
+            route_lon=-118.850000,
+        )
+        found = Trail.find_by_trailhead(
+            34.190598, -118.844015,
+            route_lat=34.192167, route_lon=-118.843143,
+            tolerance_m=100,
+        )
+        assert found is None
+
+    def test_legacy_trail_without_route_still_matches(self, db):
+        geo = GeoLocation.objects.create(lat=34.190598, lon=-118.844015)
+        trail = Trail.objects.create(
+            title="Legacy Trail",
+            trailhead_location=geo,
+        )
+        found = Trail.find_by_trailhead(
+            34.190598, -118.844015,
+            route_lat=34.192167, route_lon=-118.843143,
+            tolerance_m=100,
+        )
+        assert found == trail
+
 
 class TestFindOrCreate:
     def test_find_existing(self, db):

vrobbler/apps/scrobbles/importers/trail_gpx.py

@@ -27,6 +27,27 @@ def haversine(lat1, lon1, lat2, lon2):
     return R * 2 * asin(sqrt(a))
 
 
+def find_route_waypoint(points):
+    if not points:
+        return None
+    total = 0.0
+    for i in range(1, len(points)):
+        lat1, lon1 = points[i - 1][0], points[i - 1][1]
+        lat2, lon2 = points[i][0], points[i][1]
+        if lat1 is not None and lon1 is not None and lat2 is not None and lon2 is not None:
+            total += haversine(lat1, lon1, lat2, lon2)
+    halfway = total / 2.0
+    cumulative = 0.0
+    for i in range(1, len(points)):
+        lat1, lon1 = points[i - 1][0], points[i - 1][1]
+        lat2, lon2 = points[i][0], points[i][1]
+        if lat1 is not None and lon1 is not None and lat2 is not None and lon2 is not None:
+            cumulative += haversine(lat1, lon1, lat2, lon2)
+            if cumulative >= halfway:
+                return (lat2, lon2)
+    return (points[-1][0], points[-1][1])
+
+
 def compute_trail_stats(points):
     distance_m = 0.0
     elevation_gain = 0.0
@@ -221,15 +242,27 @@ def import_trail_gpx(file_path, user_id, original_filename=None):
         logger.warning(f"No timestamps in {file_path}")
         return []
 
+    route_pt = find_route_waypoint(points)
+
     geo, _ = GeoLocation.objects.get_or_create(
         lat=round(first_lat, 6),
         lon=round(first_lon, 6),
         defaults={"altitude": None},
     )
 
-    trail = Trail.find_by_trailhead(first_lat, first_lon, tolerance_m=100)
+    trail = Trail.find_by_trailhead(
+        first_lat, first_lon,
+        route_lat=route_pt[0] if route_pt else None,
+        route_lon=route_pt[1] if route_pt else None,
+        tolerance_m=100,
+    )
     if not trail:
-        trail = Trail.objects.create(title=track_name, trailhead_location=geo)
+        trail = Trail.objects.create(
+            title=track_name,
+            trailhead_location=geo,
+            route_lat=route_pt[0] if route_pt else None,
+            route_lon=route_pt[1] if route_pt else None,
+        )
 
     timestamp = first_time
     stop_timestamp = last_time

vrobbler/apps/trails/migrations/0009_trail_route_waypoint.py

@@ -0,0 +1,23 @@
+# Generated by Django 4.2.29 on 2026-05-21 19:58
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("trails", "0008_alter_trail_genre"),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name="trail",
+            name="route_lat",
+            field=models.FloatField(blank=True, null=True),
+        ),
+        migrations.AddField(
+            model_name="trail",
+            name="route_lon",
+            field=models.FloatField(blank=True, null=True),
+        ),
+    ]

vrobbler/apps/trails/models.py

@@ -61,6 +61,8 @@ class Trail(ScrobblableMixin):
         on_delete=models.DO_NOTHING,
         **BNULL,
     )
+    route_lat = models.FloatField(**BNULL)
+    route_lon = models.FloatField(**BNULL)
     strava_id = models.CharField(max_length=255, **BNULL)
     trailforks_id = models.CharField(max_length=255, **BNULL)
     alltrails_id = models.CharField(max_length=255, **BNULL)
@@ -91,7 +93,7 @@ class Trail(ScrobblableMixin):
         return trail
 
     @classmethod
-    def find_by_trailhead(cls, lat, lon, tolerance_m=100):
+    def find_by_trailhead(cls, lat, lon, tolerance_m=100, route_lat=None, route_lon=None):
         candidates = cls.objects.filter(
             trailhead_location__isnull=False,
         ).select_related("trailhead_location")
@@ -100,9 +102,14 @@ class Trail(ScrobblableMixin):
         for trail in candidates:
             loc = trail.trailhead_location
             d = haversine(lat, lon, loc.lat, loc.lon)
-            if d < best_dist and d <= tolerance_m:
-                best = trail
-                best_dist = d
+            if d >= best_dist or d > tolerance_m:
+                continue
+            if route_lat is not None and trail.route_lat is not None:
+                route_dist = haversine(route_lat, route_lon, trail.route_lat, trail.route_lon)
+                if route_dist > tolerance_m:
+                    continue
+            best = trail
+            best_dist = d
         return best
 
     def scrobbles(self, user_id):