定时刷新数据时，地图上会有阴影echarts effectScatter配置项内容和展示

（1）定时向后台通过ajax请求不同的地理位置信息数据时，并且是lineStyle下normal的opacity为0，lines中会基于第一次出现的lines做展示，比如第一次lines出现10条，第二次数据为12条时canvas绘制时只会出现2条 （2）定时向后台刷新数据时，第二次展示时，会是第一次的绘制的图形会有阴影在地图上

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