From d5bcecb3457f6b878995c078eb7a4811988c0f9f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ullrich=20Sch=C3=A4fer?= <hi+github@ullrich.is>
Date: Thu, 2 Apr 2026 20:19:55 +0100
Subject: [PATCH] Fix distance calculation for GPX files without elevation data

Distance was only stored in the elevation profile array, which was
empty when track points had no <ele> elements. Now computed via
haversine independently and exposed as gpxData.distance.

Tested: berlin-dresden-radweg-2021.gpx (5660 points, no elevation)
now correctly reports 248.8 km.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
---
 apps/journal/app/lib/activities.server.ts | 3 +--
 apps/journal/app/lib/routes.server.ts     | 6 +-----
 packages/gpx/src/parse.ts                 | 8 ++++----
 packages/gpx/src/types.ts                 | 2 ++
 4 files changed, 8 insertions(+), 11 deletions(-)

diff --git a/apps/journal/app/lib/activities.server.ts b/apps/journal/app/lib/activities.server.ts
index 4e48b8c..e3a399c 100644
--- a/apps/journal/app/lib/activities.server.ts
+++ b/apps/journal/app/lib/activities.server.ts
@@ -23,8 +23,7 @@ export async function createActivity(ownerId: string, input: ActivityInput) {
   if (input.gpx) {
     try {
       const gpxData = await parseGpxAsync(input.gpx);
-      const profile = gpxData.elevation.profile;
-      distance = profile.length > 0 ? Math.round(profile[profile.length - 1]!.distance) : null;
+      distance = gpxData.distance || null;
       elevationGain = gpxData.elevation.gain;
       elevationLoss = gpxData.elevation.loss;
 
diff --git a/apps/journal/app/lib/routes.server.ts b/apps/journal/app/lib/routes.server.ts
index c9f1b45..e8bd8d3 100644
--- a/apps/journal/app/lib/routes.server.ts
+++ b/apps/journal/app/lib/routes.server.ts
@@ -145,11 +145,7 @@ async function computeRouteStats(gpxString: string) {
   try {
     const gpxData = await parseGpxAsync(gpxString);
     return {
-      distance: Math.round(
-        gpxData.elevation.profile.length > 0
-          ? gpxData.elevation.profile[gpxData.elevation.profile.length - 1]!.distance
-          : 0,
-      ),
+      distance: gpxData.distance,
       elevationGain: gpxData.elevation.gain,
       elevationLoss: gpxData.elevation.loss,
     };
diff --git a/packages/gpx/src/parse.ts b/packages/gpx/src/parse.ts
index d1b118b..70a3a0e 100644
--- a/packages/gpx/src/parse.ts
+++ b/packages/gpx/src/parse.ts
@@ -46,9 +46,9 @@ function parseGpxWithParser(parser: DOMParser, xml: string): GpxData {
   const name = doc.querySelector("metadata > name")?.textContent ?? undefined;
   const waypoints = parseWaypoints(doc);
   const tracks = parseTracks(doc);
-  const elevation = computeElevation(tracks);
+  const { totalDistance, ...elevation } = computeElevation(tracks);
 
-  return { name, waypoints, tracks, elevation };
+  return { name, waypoints, tracks, distance: totalDistance, elevation };
 }
 
 function parseWaypoints(doc: Document): Waypoint[] {
@@ -85,7 +85,7 @@ function parseTracks(doc: Document): TrackPoint[][] {
   return tracks;
 }
 
-function computeElevation(tracks: TrackPoint[][]): GpxData["elevation"] {
+function computeElevation(tracks: TrackPoint[][]): GpxData["elevation"] & { totalDistance: number } {
   let gain = 0;
   let loss = 0;
   const profile: ElevationProfile[] = [];
@@ -112,7 +112,7 @@ function computeElevation(tracks: TrackPoint[][]): GpxData["elevation"] {
     }
   }
 
-  return { gain: Math.round(gain), loss: Math.round(loss), profile };
+  return { totalDistance: Math.round(totalDistance), gain: Math.round(gain), loss: Math.round(loss), profile };
 }
 
 /** Haversine distance between two points in meters */
diff --git a/packages/gpx/src/types.ts b/packages/gpx/src/types.ts
index d7861cc..bb7d0a2 100644
--- a/packages/gpx/src/types.ts
+++ b/packages/gpx/src/types.ts
@@ -18,6 +18,8 @@ export interface GpxData {
   name?: string;
   waypoints: Waypoint[];
   tracks: TrackPoint[][];
+  /** Total distance in meters (haversine, works with or without elevation data) */
+  distance: number;
   elevation: {
     gain: number;
     loss: number;