Use true, not naïve, centroid

map.html

@@ -28,7 +28,7 @@
         .label div {
             position: relative;
             left: -50%;
-            top: 10px;
+            top: -50%;
             text-shadow: 0 0 2px white;
         }
         .leaflet-popup-content-wrapper {
@@ -139,6 +139,28 @@
                 </div>`;
             document.getElementById('lightbox').style.display = 'block';
         }
+        function calculateCentroid(points) {
+            // https://en.wikipedia.org/wiki/Centroid#Of_a_polygon
+            let area = 0;
+            let centroidLat = 0;
+            let centroidLng = 0;
+
+            for (let i = 0; i < points.length; i++) {
+                const { lat: lat1, lng: lng1 } = points[i];
+                const { lat: lat2, lng: lng2 } = points[(i + 1) % points.length]; // Next vertex, wrapping around
+
+                const determinant = lat1 * lng2 - lng1 * lat2;
+                area += determinant;
+                centroidLat += (lat1 + lat2) * determinant;
+                centroidLng += (lng1 + lng2) * determinant;
+            }
+
+            area *= 0.5;
+            centroidLat /= (6 * area);
+            centroidLng /= (6 * area);
+
+            return [centroidLat, centroidLng];
+        }
         (async function() {
             const map = L.map('map', {
                 minZoom: 15,
@@ -177,13 +199,8 @@
             L.geoJSON(plats, {
                 filter: feature => !feature.properties.TAO_NAME.toLowerCase().includes("lawrence deer club"),
                 onEachFeature: function(feature, layer) {
-                    const latLngs = layer.getLatLngs()[0];
+                    const centroid = calculateCentroid(layer.getLatLngs()[0]);
-                    const centerish = [ // TODO: actual centroid
+                    const label = L.marker(centroid, {
-                        latLngs.reduce((acc, i) => acc + i.lat, 0) / latLngs.length,
-                        latLngs.reduce((acc, i) => acc + i.lng, 0) / latLngs.length,
-                    ];
-
-                    const label = L.marker(centerish, {
                         icon: L.divIcon({
                             iconSize: null,
                             className: "label",