Fix GeoJSON to cover 180th meridian quirk

See mapbox/mapbox-gl-js#3250 (comment) and related thread for further info
frederickobrien · Dec 5, 2022 · f6d4e20 · f6d4e20
1 parent e31d8ff
commit f6d4e20
Showing 1 changed file with 14 additions and 3 deletions.
diff --git a/data/books/convert-routes-to-geojson.ts b/data/books/convert-routes-to-geojson.ts
@@ -12,9 +12,20 @@ csvsInDir.forEach((file) => {
     .formatValueByType()
     .getJsonFromCsv(file);
 
-  const fullRoute = bookJson.map((entry) => {
-    const coords = [entry.Longitude, entry.Latitude];
-    return coords;
+  const fullRoute = bookJson.map((entry, i) => {
+    if (i === 0) return [entry.Longitude, entry.Latitude];
+    else {
+      const previousLongitude = bookJson[i - 1].Longitude;
+      const latitude = entry.Latitude;
+      const longitude = (entry.Longitude +=
+        entry.Longitude - previousLongitude > 180
+          ? -360
+          : previousLongitude - entry.Longitude > 180
+          ? 360
+          : 0);
+      const coords = [longitude, latitude];
+      return coords;
+    }
   });
 
   const geoJson = {