如何自定义czml数据源？

Question

我有一个通过 python 提取的 CZML 数据。我有建筑物，包括它们的几何形状、高度、建筑物 ID 和间隔。每个间隔都有一个值。将czml数据加载到Cesium后，我想访问属性，然后根据给定的值自定义建筑物的颜色。这是我的 CZML 示例：

[{ "id": "document", "version": "1.0" }, { "id": 32, "availability": "2014-01-01T00:00:00Z/2014-12-31T00:00:00Z", "polygon": { "positions": { "cartographicDegrees": [54.7162360431897, 24.4519912715277, 0, 54.716219612921, 24.4519754832587, 0, 54.7162501395131, 24.4519488635358, 0, 54.7162465684811, 24.4519454316688, 0, 54.7162670831639, 24.4519275432238, 0, 54.7162707308589, 24.4519310439514, 0, 54.7163022563025, 24.4519035537608, 0, 54.7161962974502, 24.4518018819532, 0, 54.7161647729823, 24.4518293730395, 0, 54.7162035538772, 24.4520196028966, 0, 54.7162360431897, 24.4519912715277, 0] }, "someProperty": [{ "interval": "2014-00-01T00:00:00Z/2014-01-01T00:00:00Z", "En_C_need": 0.7 }, { "interval": "2014-01-01T00:00:00Z/2014-02-01T00:00:00Z", "En_C_need": 1.0 }, { "interval": "2014-02-01T00:00:00Z/2014-03-01T00:00:00Z", "En_C_need": 2.6 }, { "interval": "2014-03-01T00:00:00Z/2014-04-01T00:00:00Z", "En_C_need": 12.1 }, { "interval": "2014-04-01T00:00:00Z/2014-05-01T00:00:00Z", "En_C_need": 30.2 }, { "interval": "2014-05-01T00:00:00Z/2014-06-01T00:00:00Z", "En_C_need": 37.8 }], "extrudedHeight": 6.0 } }]

我还有其他自定义的GeoJSON数据，我尝试了同样的方法，但没有用。

这是我正在尝试做的（这不起作用）：

var test2 = Cesium.CzmlDataSource.load ('Data/czml/TESTING/example_8.czml');
test2.then(function (dataSource) {
    viewer.dataSources.add(test2);
    viewer.zoomTo (test2);
var entities = dataSource.entities.values; 

    var colorHash = {};
    var Energy = [];
    for (var i = 0; i < entities.length; i++) {
        var entity = entities[i];
        Energy = entity.someProperty.En_C_need;
        var color = colorHash [Energy];
        if(!color ) {
            if (Energy < 5 ) {
            color = Cesium.Color.DARKSALMON.withAlpha (0.95);
        } else if (Energy < 10) {
                color = Cesium.Color.BURLYWOOD.withAlpha (0.95);
        } else if (Energy < 20) {
                color = Cesium.Color.RED.withAlpha (0.95);
        } else {
                color = Cesium.Color.PINK.withAlpha (0.95); 
        };
        colorHash[Energy] = color;
        };
        entity.polygon.fill = true;
        entity.polygon.material = color;
        entity.polygon.outline = false;     
    };

});

Answer 1

从解决方案开始 - 这是工作 plnkr： https://plnkr.co/edit/P1Cg4DNJYtK9r9XrLzxK?p=preview

我已经更改了您的代码中的几处内容： 1) viewer.dataSources.add(test2); 应该在你的承诺之外（这并不重要，但它是更清晰的代码 - 在承诺中使用承诺感觉很奇怪）。 2) 根据 CZML 属性规范，您需要将属性放在 CZML 中的正确位置。它不应该在多边形内部，而是在 "root":

var czml = [{"id": "document", "version": "1.0"},
{
    "id": 32, "availability": "2014-01-01T00:00:00Z/2014-12-31T00:00:00Z", "properties": {
    "someProperty": [
        {"interval": "2014-00-01T00:00:00Z/2014-01-01T00:00:00Z", "En_C_need": 0.7}, 
        {"interval": "2014-01-01T00:00:00Z/2014-02-01T00:00:00Z", "En_C_need": 1.0},
        {"interval": "2014-02-01T00:00:00Z/2014-03-01T00:00:00Z", "En_C_need": 2.6},
        {"interval": "2014-03-01T00:00:00Z/2014-04-01T00:00:00Z", "En_C_need": 12.1},
        {"interval": "2014-04-01T00:00:00Z/2014-05-01T00:00:00Z", "En_C_need": 30.2},
        {"interval": "2014-05-01T00:00:00Z/2014-06-01T00:00:00Z", "En_C_need": 37.8}
        ],
},
    "polygon": {
        "positions": {
            "cartographicDegrees":
                [54.7162360431897, 24.4519912715277, 0, 54.716219612921, 24.4519754832587, 0, 54.7162501395131, 24.4519488635358, 0, 54.7162465684811, 24.4519454316688, 0, 54.7162670831639, 24.4519275432238, 0, 54.7162707308589, 24.4519310439514, 0, 54.7163022563025, 24.4519035537608, 0, 54.7161962974502, 24.4518018819532, 0, 54.7161647729823, 24.4518293730395, 0, 54.7162035538772, 24.4520196028966, 0, 54.7162360431897, 24.4519912715277, 0]
        },
        "extrudedHeight": 6.0
    }
}];

然后可以根据时间间隔(Energy = entity.properties.getValue(viewer.clock.currentTime).someProperty.En_C_need;)查询属性，得到观众当前时间的能量。

评论后更新：您的代码无意动态更改。您需要通过 callbackProperty 设置值，如本示例所示：plnkr.co/edit/lm290uaQewEvfIOgXbDP?p=preview 或使用 timeIntervalCollection

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