getCirclePoints static method

List<LatLng> getCirclePoints({
  1. required LatLng center,
  2. required double radiusMi,
  3. int pointLen = 10,
})

获取一串正圆坐标,可以利用多边形绘制圆

Implementation

//@radiusMi:半径(米)
static List<LatLng> getCirclePoints({required LatLng center, required double radiusMi,int pointLen = 10}) {
  List<LatLng> points = [];//此参数用于存储多边形的经纬度,
  //地球周长
  double perimeter =  2*math.pi*6371000;
  //纬度latitude的地球周长:latitude
  double perimeterLatitude = perimeter*math.cos(math.pi * center.latitude / 180);
  //一米对应的经度(东西方向)1M实际度
  double lngRate = 360 / perimeterLatitude;
  double latRate = 360 / perimeter;
  //10度转角度
  double phase = (2 * math.pi/360) * pointLen;
  for (int i = 0; i <= 360/pointLen; i++) {
    points.add(LatLng(
        center.latitude + math.sin(phase*i)*latRate* radiusMi ,
        center.longitude - math.cos(phase*i)*lngRate* radiusMi
    ));
  }
  return points;
}