stab at fixing antimeridian issues

src/components/WorldMap.jsx

@@ -538,14 +538,24 @@ export const WorldMap = ({
             );
             
             // Validate points before creating polyline
-            if (points && points.length > 1 && points.every(p => Array.isArray(p) && !isNaN(p[0]) && !isNaN(p[1]))) {
-              const line = L.polyline(points, {
-                color: bandColor,
-                weight: 1.5,
-                opacity: 0.5,
-                dashArray: '4, 4'
-              }).addTo(map);
-              pskMarkersRef.current.push(line);
+            // getGreatCirclePoints returns array of segments (each segment is array of [lat,lon])
+            if (points && Array.isArray(points) && points.length > 0) {
+              // Check if it's segmented (array of arrays of points) or flat (single segment)
+              const isSegmented = Array.isArray(points[0]) && points[0].length > 0 && Array.isArray(points[0][0]);
+              const segments = isSegmented ? points : [points];
+              
+              segments.forEach(segment => {
+                if (segment && Array.isArray(segment) && segment.length > 1 && 
+                    segment.every(p => Array.isArray(p) && !isNaN(p[0]) && !isNaN(p[1]))) {
+                  const line = L.polyline(segment, {
+                    color: bandColor,
+                    weight: 1.5,
+                    opacity: 0.5,
+                    dashArray: '4, 4'
+                  }).addTo(map);
+                  pskMarkersRef.current.push(line);
+                }
+              });
             }
             
             // Add small dot marker at spot location

src/utils/geo.js

@@ -210,15 +210,26 @@ export const getGreatCirclePoints = (lat1, lon1, lat2, lon2, n = 100) => {
   let currentSegment = [rawPoints[0]];
   
   for (let i = 1; i < rawPoints.length; i++) {
+    const prevLat = rawPoints[i-1][0];
     const prevLon = rawPoints[i-1][1];
+    const currLat = rawPoints[i][0];
     const currLon = rawPoints[i][1];
     
     // Check if we crossed the antimeridian (lon jumps more than 180°)
     if (Math.abs(currLon - prevLon) > 180) {
-      // Finish current segment
+      // Interpolate the crossing point
+      // Normalize longitudes so the crossing is smooth
+      const prevLonAdj = prevLon;
+      const currLonAdj = currLon > prevLon ? currLon - 360 : currLon + 360;
+      const frac = (prevLon > 0 ? 180 - prevLon : -180 - prevLon) / (currLonAdj - prevLonAdj);
+      const crossLat = prevLat + frac * (currLat - prevLat);
+      
+      // End current segment at the map edge
+      currentSegment.push([crossLat, prevLon > 0 ? 180 : -180]);
       segments.push(currentSegment);
-      // Start new segment
-      currentSegment = [];
+      
+      // Start new segment from the opposite edge
+      currentSegment = [[crossLat, prevLon > 0 ? -180 : 180]];
     }
     currentSegment.push(rawPoints[i]);
   }