From 2fe21cab247a41cee50aaa8da4a3f5ab451e7d3a Mon Sep 17 00:00:00 2001
From: you <you@example.com>
Date: Thu, 19 Mar 2026 08:26:37 +0000
Subject: [PATCH] Fix observer location for hop disambiguation

- ADVERT is payload_type 4 not 1
- Frontend sends observer_id (not just observer_name) since some
  observers have null name
- Observer position derived from geographic center of nodes it
  commonly receives ADVERTs from
- Last hop in path disambiguated by proximity to observer position
---
 public/packets.js |  3 ++-
 server.js         | 16 ++++++++++------
 2 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/public/packets.js b/public/packets.js
index ea9da8e6..9bd691b5 100644
--- a/public/packets.js
+++ b/public/packets.js
@@ -505,7 +505,8 @@
     if (routeBtn && pathHops.length) {
       routeBtn.addEventListener('click', async () => {
         try {
-          const observerParam = pkt.observer_name ? '&observer=' + encodeURIComponent(pkt.observer_name) : '';
+          const obsId = pkt.observer_name || pkt.observer_id || '';
+          const observerParam = obsId ? '&observer=' + encodeURIComponent(obsId) : '';
           const resp = await fetch('/api/resolve-hops?hops=' + encodeURIComponent(pathHops.join(',')) + observerParam);
           const data = await resp.json();
           // Pass full pubkeys (server-disambiguated) to map, falling back to short prefix
diff --git a/server.js b/server.js
index 9e01e1ac..15b9b465 100644
--- a/server.js
+++ b/server.js
@@ -912,13 +912,17 @@ app.get('/api/resolve-hops', (req, res) => {
       observerLat = obsNode.lat;
       observerLon = obsNode.lon;
     } else {
-      // Fall back to averaging nodes it typically hears
+      // Fall back to averaging nearby nodes from adverts this observer received
       const obsNodes = db.db.prepare(`
-        SELECT DISTINCT n.lat, n.lon FROM packets p
-        JOIN nodes n ON p.decoded_json LIKE '%' || n.public_key || '%'
-        WHERE p.observer_id = ? AND n.lat IS NOT NULL AND n.lat != 0 AND n.lon != 0
-        LIMIT 50
-      `).all(observerId);
+        SELECT n.lat, n.lon FROM packets p
+        JOIN nodes n ON n.public_key = json_extract(p.decoded_json, '$.pubKey')
+        WHERE (p.observer_id = ? OR p.observer_name = ?)
+          AND p.payload_type = 4
+          AND n.lat IS NOT NULL AND n.lat != 0 AND n.lon != 0
+        GROUP BY n.public_key
+        ORDER BY COUNT(*) DESC
+        LIMIT 20
+      `).all(observerId, observerId);
       if (obsNodes.length) {
         observerLat = obsNodes.reduce((s, n) => s + n.lat, 0) / obsNodes.length;
         observerLon = obsNodes.reduce((s, n) => s + n.lon, 0) / obsNodes.length;