/// <summary>
///
/// </summary>
/// <param name="level"></param>
/// <param name="itemEnv"></param>
private void ComputeKey(int level, IEnvelope itemEnv)
{
double quadSize = DoubleBits.PowerOf2(level);
pt.X = Math.Floor(itemEnv.MinX / quadSize) * quadSize;
pt.Y = Math.Floor(itemEnv.MinY / quadSize) * quadSize;
env.Init(pt.X, pt.X + quadSize, pt.Y, pt.Y + quadSize);
}
