calculatePolygonWithHolesArea static method

double calculatePolygonWithHolesArea(List<LatLng> outerPolygon, List<List<LatLng>> holes)

Calculate the area of a polygon with holes.

outerPolygon - A list of LatLng coordinates representing the vertices of the outer polygon. holes - A list of holes, where each hole is represented as a list of LatLng coordinates.

Returns the area of the polygon with holes in square meters.

Implementation

static double calculatePolygonWithHolesArea(
    List<LatLng> outerPolygon, List<List<LatLng>> holes) {
  // Calculate and sum the areas of holes
  final holeAreas = holes.map((hole) {
    double area = 0.0;
    for (int i = 0; i < hole.length; i++) {
      final j = (i + 1) % hole.length;
      area += (hole[i].longitude + hole[j].longitude) *
          (hole[j].latitude - hole[i].latitude);
    }
    return area / 2.0;
  }).toList();

  // Calculate the area of the outer polygon
  double outerArea = 0.0;
  for (int i = 0; i < outerPolygon.length; i++) {
    final j = (i + 1) % outerPolygon.length;
    outerArea += (outerPolygon[i].longitude + outerPolygon[j].longitude) *
        (outerPolygon[j].latitude - outerPolygon[i].latitude);
  }

  // Subtract hole areas from the outer area to get the final area
  final finalArea =
      (outerArea / 2.0 - holeAreas.reduce((a, b) => a + b)).abs();

  return finalArea;
}