如何使用GMap.Net绘制热图

这是我找到的一条指令http://blog.ethereal-engineering.com/2013/01/heatmaps-using-gheat-and-gmap.html.

如何添加这个

  private decimal? weight;
  private object data;
  public decimal? Weight { get { return weight; } set { weight = value; } }
  public object Data { get { return data; } set { data = value; } }

到GMap。