2021-10-09--cesium加载面时出现面压住面情况解决

在新做的cesium加载等值面功能中，地形上加载贴地面出现挤压现象，先记录解决办法

解决办法很简单，给 zIndex赋值，

 res.entities.values.forEach((fea, index) => {
    const entity = new Cesium.Entity({
        id: fea.id,
        polygon: new Cesium.PolygonGraphics({
            hierarchy: fea.polygon.hierarchy,
            //height: 1500,
            heightReference: Cesium.HeightReference.CLAMP_TO_GROUND,
            //extrudedHeight: fea.properties.hvalue * 20,
            // extrudedHeightReference: Cesium.HeightReference.CLAMP_TO_GROUND,
            // classificationType: Cesium.ClassificationType.TERRAIN,
            material: this.getLevelColor(fea.properties),
            arcType: Cesium.ArcType.RHUMB,
            zIndex: index,
            //perPositionHeight: true,
        }),
    });

this.dataSource.entities.add(entity);
});