MultiPolygon.fromJson constructor Null safety

  1. @override
MultiPolygon.fromJson(
  1. Map<String, dynamic> json
)

Creates a MultiPolygon from a GeoJSON Map.

Example:

MultiPolygon.fromJson({'type': 'Feature', 'geometry': {'type': 'MultiPolygon', 'coordinates': [[[[1, 2], [3, 4], [5, 6], [1, 2]]], [[[7, 8], [9, 10], [11, 12], [7, 8]]]]}, 'properties': {}}); // MultiPolygon([[LinearRing([Coordinate(1, 2), Coordinate(3, 4), Coordinate(5, 6), Coordinate(1, 2)]), LinearRing([Coordinate(7, 8), Coordinate(9, 10), Coordinate(11, 12), Coordinate(7, 8)])]])

Implementation

@override
factory MultiPolygon.fromJson(Map<String, dynamic> json) {
  if (json['geometry']['type'] != 'MultiPolygon') {
    throw ArgumentError('json is not a MultiPolygon');
  }

  return MultiPolygon(
    (json['geometry']['coordinates'] as List<List<List<List<double>>>>)
        .map((dynamic poly) => (poly as List<List<List<double>>>)
            .map((dynamic shape) => LinearRing((shape as List<List<double>>)
                .map((dynamic coord) => Coordinate.fromJson(coord))
                .toList()))
            .toList())
        .toList(),
    properties: Map<String, dynamic>.from(json['properties']),
  );
}