diff --git a/server/index.js b/server/index.js
index bc32455..9ceb0e5 100644
--- a/server/index.js
+++ b/server/index.js
@@ -12,13 +12,10 @@ const DIST = join(ROOT, 'dist')
 const SAVES_DIR = join(ROOT, 'data', 'saves')
 const DB_PATH = join(ROOT, 'data', 'otivm.sqlite3')
 
-// Ensure saves directory exists
 await mkdir(SAVES_DIR, { recursive: true })
 
-// Open TESSERA database — read-only
 const db = new Database(DB_PATH, { readonly: true })
 
-// Prepared statements
 const stmtEpoch = db.prepare(
   'SELECT sl_offset_cm FROM paleo_epochs WHERE epoch_key = ?'
 )
@@ -26,45 +23,41 @@ const stmtEpoch = db.prepare(
 const stmtH7 = db.prepare(`
   SELECT
     h7,
-    SUM(CASE WHEN elev_cm > ? THEN 1 ELSE 0 END) AS h7_land,
-    COUNT(*) AS h9_total
+    AVG(lat)                                                  AS lat,
+    AVG(lon)                                                  AS lon,
+    SUM(CASE WHEN elev_cm > ? THEN 1 ELSE 0 END)             AS h7_land,
+    COUNT(*)                                                  AS h9_total
   FROM tessera_cells
   WHERE h5 = ? AND status = 2
   GROUP BY h7
 `)
 
-// Convert hex string H3 ID to BigInt integer for DB lookup
 function h3HexToInt(hexStr) {
   return BigInt('0x' + hexStr)
 }
 
 const fastify = Fastify({ logger: false })
 
-// Serve built frontend
 await fastify.register(fastifyStatic, {
   root: DIST,
   prefix: '/',
 })
 
-// --- TESSERA map endpoint ---
-// Returns H7-aggregated land/sea classification for one H5 waypoint at one epoch.
-// h5param: H3 res-5 cell ID as hex string (e.g. '851e805bfffffff')
+// GET /api/map/:h5/:epoch
+// Returns H7-aggregated land/sea classification with real centroids.
+// h5param: H3 res-5 hex string (e.g. '851e805bfffffff')
 // epochKey: named epoch from paleo_epochs (e.g. 'roman_14bce')
-// Response: { epoch_key, sl_offset_cm, h5, cells: [{ h7, h7_land, h9_total, is_land }] }
+// Response: { epoch_key, sl_offset_cm, h5, cells: [{ h7, lat, lon, h7_land, h9_total, is_land }] }
 fastify.get('/api/map/:h5/:epoch', async (req, reply) => {
   const { h5: h5param, epoch: epochKey } = req.params
 
-  // Validate H5 — must be 15-char lowercase hex
   if (!/^[0-9a-f]{15}$/.test(h5param)) {
     return reply.code(400).send({ error: 'Invalid H5 ID' })
   }
-
-  // Validate epoch key — alphanumeric and underscores only
   if (!/^[a-z0-9_]+$/.test(epochKey)) {
     return reply.code(400).send({ error: 'Invalid epoch key' })
   }
 
-  // Resolve epoch to sea level offset
   const epoch = stmtEpoch.get(epochKey)
   if (!epoch) {
     return reply.code(404).send({ error: `Unknown epoch: ${epochKey}` })
@@ -72,7 +65,6 @@ fastify.get('/api/map/:h5/:epoch', async (req, reply) => {
 
   const slOffsetCm = epoch.sl_offset_cm
 
-  // Convert H5 hex string to integer for DB query
   let h5int
   try {
     h5int = h3HexToInt(h5param)
@@ -80,30 +72,29 @@ fastify.get('/api/map/:h5/:epoch', async (req, reply) => {
     return reply.code(400).send({ error: 'Malformed H5 ID' })
   }
 
-  // Query H7 land/sea classification
   const rows = stmtH7.all(slOffsetCm, h5int)
 
   if (!rows.length) {
     return reply.code(404).send({ error: `No data for H5: ${h5param}` })
   }
 
-  // Apply majority rule: H7 cell is land if >50% of H9 children are land
   const cells = rows.map(row => ({
-    h7: row.h7.toString(16),          // return as hex string
-    h7_land: row.h7_land,
+    h7:       row.h7.toString(16),
+    lat:      row.lat,
+    lon:      row.lon,
+    h7_land:  row.h7_land,
     h9_total: row.h9_total,
-    is_land: row.h7_land * 2 > row.h9_total ? 1 : 0,
+    is_land:  row.h7_land * 2 > row.h9_total ? 1 : 0,
   }))
 
   return reply.send({
-    epoch_key: epochKey,
+    epoch_key:    epochKey,
     sl_offset_cm: slOffsetCm,
-    h5: h5param,
+    h5:           h5param,
     cells,
   })
 })
 
-// Load save state
 fastify.get('/api/save/:token', async (req, reply) => {
   const { token } = req.params
   if (!/^[0-9a-f]{8}$/.test(token)) {
@@ -121,7 +112,6 @@ fastify.get('/api/save/:token', async (req, reply) => {
   }
 })
 
-// Write save state
 fastify.post('/api/save/:token', async (req, reply) => {
   const { token } = req.params
   if (!/^[0-9a-f]{8}$/.test(token)) {
@@ -139,7 +129,6 @@ fastify.post('/api/save/:token', async (req, reply) => {
   }
 })
 
-// Fallback — serve index.html for client-side routing
 fastify.setNotFoundHandler((req, reply) => {
   reply.sendFile('index.html')
 })