绘制圆形，方法一（Canvas，drawOval）

[code] private int mRadius=6；

/*假设有一个GeoPoint gp，存储着卫星坐标对*/

/*设置笔刷*/

Paint paint = new Paint();

paint.setAntiAlias(true);//抗锯齿

paint.setColor(Color.BLUE);

Projection projection = mapView.getProjection();

Point point = new Point();

projection.toPixels(gp,point);//把gp转换成point，int类型

/*定义RectF对象*/

RectF oval = new RectF(point.x - mRadius, point.y - mRadius,

point.x + mRadius, point.y + mRadius);

/*绘制起点的圆形*/

canvas.drawOval(oval.paint);