void AddCircles()
        {
            var circle1 = new MapCircle
                          (
                MapPoint.MapPointWithGeoCoord(37.537094, 127.005470), // center
                500,                                                  // radius
                Color.Argb(128, 255, 0, 0),                           // strokeColor
                Color.Argb(128, 0, 255, 0)                            // fillColor
                          );

            circle1.Tag = 1234;
            mMapView.AddCircle(circle1);
            var circle2 = new MapCircle
                          (
                MapPoint.MapPointWithGeoCoord(37.551094, 127.019470), // center
                1000,                                                 // radius
                Color.Argb(128, 255, 0, 0),                           // strokeColor
                Color.Argb(128, 255, 255, 0)                          // fillColor
                          );

            circle2.Tag = 5678;
            mMapView.AddCircle(circle2);

            // 지도뷰의 중심좌표와 줌레벨을 Circle이 모두 나오도록 조정.
            MapPointBounds[] mapPointBoundsArray = { circle1.Bound, circle2.Bound };
            MapPointBounds   mapPointBounds      = new MapPointBounds(mapPointBoundsArray);
            int padding = 50; // px

            mMapView.MoveCamera(CameraUpdateFactory.NewMapPointBounds(mapPointBounds, padding));
        }