centroid = (feature) => {
const geometry = feature.geometry;
if (geometry.type === "Polygon"){
return d3.geoCentroid(feature);
}
else {
let largestPolygon = {}, largestArea = 0;
geometry.coordinates.forEach(coordinates => {
const polygon = { type: "Polygon", coordinates },
area = d3.geoArea(polygon);
if (area > largestArea) {
largestPolygon = polygon;
largestArea = area;
}
});
return d3.geoCentroid(largestPolygon);
}
}