findPolygonCentroid static method

LatLng findPolygonCentroid(List<LatLng> polygons)

Finds the centroid of a polygon defined by a list of LatLng points.

polygons - A list of LatLng coordinates representing the vertices of the polygon.

Returns the centroid of the polygon as a LatLng object.

Implementation

static LatLng findPolygonCentroid(List<LatLng> polygons) {
  num x = 0;
  num y = 0;
  num signedArea = 0;

  num vertexCount = polygons.length;

  for (int i = 0; i < vertexCount; i++) {
    final LatLng currentVertex = polygons[i];
    final LatLng nextVertex = polygons[(i + 1) % vertexCount.toInt()];

    num a = currentVertex.longitude * nextVertex.latitude -
        nextVertex.longitude * currentVertex.latitude;
    signedArea += a;
    x += (currentVertex.longitude + nextVertex.longitude) * a;
    y += (currentVertex.latitude + nextVertex.latitude) * a;
  }

  signedArea *= 0.5;
  x /= (6 * signedArea);
  y /= (6 * signedArea);

  // Return the centroid as LatLng object
  return LatLng(
    y.toDouble(),
    x.toDouble(),
  );
}