diff --git a/gpx/src/gpx.ts b/gpx/src/gpx.ts
index 96382b99..2d73999c 100644
--- a/gpx/src/gpx.ts
+++ b/gpx/src/gpx.ts
@@ -668,11 +668,11 @@ export class TrackSegment extends GPXTreeLeaf {
     _computeSmoothedElevation(): number[] {
         const points = this.trkpt;
 
-        let smoothed = distanceWindowSmoothing(points, 100, (index) => points[index].ele, (accumulated, start, end) => accumulated / (end - start + 1));
+        let smoothed = distanceWindowSmoothing(points, 100, (index) => points[index].ele ?? 0, (accumulated, start, end) => accumulated / (end - start + 1));
 
         if (points.length > 0) {
-            smoothed[0] = points[0].ele;
-            smoothed[points.length - 1] = points[points.length - 1].ele;
+            smoothed[0] = points[0].ele ?? 0;
+            smoothed[points.length - 1] = points[points.length - 1].ele ?? 0;
         }
 
         return smoothed;
diff --git a/website/src/lib/components/toolbar/tools/routing/Routing.ts b/website/src/lib/components/toolbar/tools/routing/Routing.ts
index c5701658..42ee72fb 100644
--- a/website/src/lib/components/toolbar/tools/routing/Routing.ts
+++ b/website/src/lib/components/toolbar/tools/routing/Routing.ts
@@ -73,7 +73,7 @@ async function getRoute(points: Coordinates[], brouterProfile: string, privateRo
                 lat: coord[1],
                 lon: coord[0]
             },
-            ele: coord[2] ?? undefined
+            ele: coord[2] ?? (i > 0 ? route[i - 1].ele : 0)
         }));
         route[route.length - 1].setSurface(surface)