Implement 20x warp speed over water with land prediction and speedometer UI

backend/app/server.js

@@ -54,13 +54,32 @@ app.get('/api/line-of-sight', async (req, res) => {
     // Generate path points for visualization and spatial query
     const pathPoints = [];
     const totalDistance = 20000;
-    const steps = 40;
+    const steps = 80; // More steps for smoother speed transition
     
     for (let i = 0; i <= steps; i++) {
       const dist = (totalDistance * i) / steps;
       pathPoints.push(calculateDestination(startLat, startLon, bearing, dist));
     }
 
+    // Batch check for 'over water' status for all path points
+    // We'll consider a point 'over water' if no city is within 500km
+    const waterChecks = await Promise.all(pathPoints.map(async (p) => {
+      const checkQuery = `
+        SELECT EXISTS (
+          SELECT 1 FROM cities 
+          WHERE ST_DWithin(geom, ST_SetSRID(ST_MakePoint($1, $2), 4326)::geography, 500000)
+          LIMIT 1
+        ) as has_land;
+      `;
+      const res = await pool.query(checkQuery, [p.lon, p.lat]);
+      return !res.rows[0].has_land;
+    }));
+
+    const pathPointsWithWater = pathPoints.map((p, i) => ({
+      ...p,
+      is_over_water: waterChecks[i]
+    }));
+
     const lineWKT = `LINESTRING(${pathPoints.map(p => `${p.lon} ${p.lat}`).join(',')})`;
     
     const query = `
@@ -86,11 +105,6 @@ app.get('/api/line-of-sight', async (req, res) => {
 
     const result = await pool.query(query, [lineWKT, toleranceKm, startLon, startLat]);
     
-    console.log(`Found ${result.rows.length} conurbations near the line.`);
-    if (result.rows.length > 0) {
-      console.log('Sample result row:', result.rows[0]);
-    }
-
     res.json({
       success: true,
       data: {
@@ -104,7 +118,7 @@ app.get('/api/line-of-sight', async (req, res) => {
           distance_km: Math.round(row.distance_from_start_km),
           off_line_km: Math.round(row.distance_off_line_km)
         })),
-        line_coordinates: pathPoints
+        line_coordinates: pathPointsWithWater
       }
     });
   } catch (err) {