public GroundOverlay(Icon icon, LatLonBox box, LookAt lookat, string name, string rrggbbaa, int drawOrder, bool visibility)
     : this(icon, box)
 {
     this._lookAt = lookat;
     this._name = name;
     this._color = rrggbbaa;
     this._drawOrder = drawOrder;
     this._visibility = visibility;
 }
        bool _visibility; //optional

        #endregion Fields

        #region Constructors

        /// <summary>
        /// Simplest constructor with only required elements
        /// </summary>
        /// <param name="icon">the Icon object that defines the image of the overlay.</param>
        /// <param name="box">the LatLonBox that defines the bounds of the overlay.</param>
        public GroundOverlay(Icon icon, LatLonBox box)
        {
            this._icon = icon;
            this._latLonBox = box;
        }