我需要存储谷歌地图上绘制的所有LatLng圆点。喜欢 :
我有圆和半径(米)。怎么弄?我尝试了代码......
private ArrayList<LatLng> makeCircle(LatLng centre, double radius, float zoom)
{
ArrayList<LatLng> points = new ArrayList<LatLng>();
LatLngBounds.Builder builder = new LatLngBounds.Builder();
double EARTH_RADIUS = 6378100.0;
for (double t = 0; t <= Math.PI * 2; t += 1.0)
{
double rad = radius + zoom * EARTH_RADIUS;
double latPoint = centre.latitude + (rad / EARTH_RADIUS) * Math.sin(t);
double lonPoint = centre.longitude + (rad / EARTH_RADIUS) * Math.cos(t) / Math.cos(centre.latitude);
points.add(new LatLng(latPoint * 180.0 / Math.PI, lonPoint * 180.0 / Math.PI));
Marker customMarker = map.addMarker(new MarkerOptions()
.position(new LatLng(latPoint,lonPoint)));
builder.include(new LatLng(latPoint,lonPoint));
LatLngBounds bound = builder.build();
CameraUpdate cu = CameraUpdateFactory.newLatLngBounds(bound, width-100, height-100, 20);
map.animateCamera(cu);
}
return points;
}
但是我得到的分数却没有确切的位置。我得到了这个
如何解决这个问题?
答案 0 :(得分:9)
“缩放”因子与此处的计算无关。更新你的makeCircle()方法,如下所示,它将按照你想要的方式工作:
private ArrayList<LatLng> makeCircle(LatLng centre, double radius)
{
ArrayList<LatLng> points = new ArrayList<LatLng>();
double EARTH_RADIUS = 6378100.0;
// Convert to radians.
double lat = centre.latitude * Math.PI / 180.0;
double lon = centre.longitude * Math.PI / 180.0;
for (double t = 0; t <= Math.PI * 2; t += 0.3)
{
// y
double latPoint = lat + (radius / EARTH_RADIUS) * Math.sin(t);
// x
double lonPoint = lon + (radius / EARTH_RADIUS) * Math.cos(t) / Math.cos(lat);
// saving the location on circle as a LatLng point
LatLng point =new LatLng(latPoint * 180.0 / Math.PI, lonPoint * 180.0 / Math.PI);
// here mMap is my GoogleMap object
mMap.addMarker(new MarkerOptions().position(point));
// now here note that same point(lat/lng) is used for marker as well as saved in the ArrayList
points.add(point);
}
return points;
}
我相信它对你有帮助:)。