cesium shp居中

要将Cesium中的SHP文件居中，可以使用以下代码：

var dataSource = new Cesium.GeoJsonDataSource();
var promise = dataSource.load('./path/to/your/file.shp');

promise.then(function() {
    var entities = dataSource.entities.values;
    var west = Number.MAX_VALUE;
    var south = Number.MAX_VALUE;
    var east = Number.MIN_VALUE;
    var north = Number.MIN_VALUE;
    entities.forEach(function(entity) {
        var rectangle = entity.rectangle;
        if (rectangle) {
            west = Math.min(west, rectangle.west);
            south = Math.min(south, rectangle.south);
            east = Math.max(east, rectangle.east);
            north = Math.max(north, rectangle.north);
        }
    });

    var rectangle = Cesium.Rectangle.fromDegrees(west, south, east, north);
    var center = Cesium.Rectangle.center(rectangle);

    viewer.camera.flyTo({
        destination: center,
        duration: 3
    });
});

这个代码会加载SHP文件并获取其所有实体的边框范围，然后计算出中心点，并使用Cesium的`flyTo`方法将相机移动到该点。这样，SHP文件就会居中显示在Cesium场景中。