in src/geojson2h3.js [58:69]
function centroid(polygon) {
let lngSum = 0;
let latSum = 0;
let count = 0;
const loop = polygon[0];
for (let i = 0; i < loop.length; i++) {
lngSum += loop[i][0];
latSum += loop[i][1];
count++;
}
return [lngSum / count, latSum / count];
}