I need to store all the LatLng points of circle drawn on google map. like :
I have circle and radius(in meter). How to get that?. i tried with the code......
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;
}
but i m getting points but not on exact locations. i am getting this
How to solve this?
The 'zoom' factor is not relevant for the calculations here. Update your makeCircle() method as shown below and it will work exactly the way you want:
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;
}
I am sure it helped you :)
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