如何将轨迹方向添加到 CZML 文件

Question

我有一个 czml 文件，它表示飞行指定路径的飞机。该文件基于 Cesiusm 提供的 Sancastle 示例构建（CZML 模型 + CZML 路径）。

这里是 CZML 变量：

var czml = [{
    "id" : "document",
    "name" : "CZML Path",
    "version" : "1.0",
    "clock": {
        "interval": "2012-08-04T10:00:00Z/2012-08-04T15:00:00Z",
        "currentTime": "2012-08-04T10:00:00Z",
        "multiplier": 10
    }
}, {
    "id" : "path",
    "name" : "path with GPS flight data",
    "description" : "<p>Hang gliding flight log data from Daniel H. Friedman.<br>Icon created by Larisa Skosyrska from the Noun Project</p>",
    "availability" : "2012-08-04T10:00:00Z/2012-08-04T15:00:00Z",
    "path" : {
        "material" : {
            "polylineOutline" : {
                "color" : {
                    "rgba" : [255, 0, 255, 255]
                },
                "outlineColor" : {
                    "rgba" : [0, 255, 255, 255]
                },
                "outlineWidth" : 5
            }
        },
        "width" : 8,
        "leadTime" : 10,
        "trailTime" : 1000,
        "resolution" : 5
    },
    "model": {
        "gltf" : "../../SampleData/models/CesiumAir/Cesium_Air.glb",
        "scale" : 2.0,
        "minimumPixelSize": 128
    },
    "position" : {
        "epoch" : "2012-08-04T10:00:00Z",
        "cartographicDegrees" : [
            0,-122.93797,39.50935,1776,
            10,-122.93822,39.50918,1773,
            20,-122.9385,39.50883,1772,
            30,-122.93855,39.50842,1770,
            40,-122.93868,39.50792,1770,
            50,-122.93877,39.50743,1767,
            60,-122.93862,39.50697,1771,
            70,-122.93828,39.50648,1765,
            80,-122.93818,39.50608,1770,
            90,-122.93783,39.5057,1754,
            100,-122.93777,39.50513,1732,
            110,-122.93793,39.50458,1727,
            120,-122.93815,39.50415,1717,
            130,-122.9382,39.50362,1713,
            140,-122.93818,39.5031,1703,
            150,-122.93812,39.50258,1706,
            160,-122.93792,39.5022,1707,
            170,-122.93775,39.50177,1698,
            180,-122.93745,39.50125,1693,
            190,-122.93723,39.50073,1694,
            200,-122.9373,39.50023,1702
        ]
    }
}];

为了能够运行代码，我还添加了以下几行：

var terrainProvider = new Cesium.CesiumTerrainProvider({
url : 'https://assets.agi.com/stk-terrain/v1/tilesets/world/tiles',
requestVertexNormals : true
});

var viewer = new Cesium.Viewer('cesiumContainer', {
terrainProvider : terrainProvider,
baseLayerPicker : false
});

viewer.dataSources.add(Cesium.CzmlDataSource.load(czml)).then(function(ds) {
viewer.trackedEntity = ds.entities.getById('path');
});

如果你运行代码，你可以看到飞机的中心点是如何跟随轨迹的，但是它的航向并没有与它对齐，因此给出了一个错误的 rap 表示飞行应该是什么样子：

您能解释一下如何在不改变初始 czml 文件结构的情况下将飞机方向添加到代码中吗？

注意：我找到了answer to this question，但我无法解决我的问题。

Answer 1

我想出了我的问题的答案。这里有几行代码，如果放在 Sandcastle 中，将允许加载 czml 文件，然后通过某种类型的插值添加方向属性：

//Sandcastle_Begin
var terrainProvider = new Cesium.CesiumTerrainProvider({
url : 'https://assets.agi.com/stk-terrain/v1/tilesets/world/tiles',
requestVertexNormals : true
});

var viewer = new Cesium.Viewer('cesiumContainer', {
terrainProvider : terrainProvider,
baseLayerPicker : false
});

var options = {
    camera : viewer.scene.camera,
    canvas : viewer.scene.canvas
};

Sandcastle.addToolbarMenu([{
    text : 'Lateral avoidance w. real Wx and waypoints (KJFK-LEBL)',
    onselect : function() {

        viewer.camera.flyHome(0); 

        viewer.dataSources.add(Cesium.CzmlDataSource.load('./SampleData/interp_turb_data_fromFede_avoid_realistic_w_waypoints.czml')).then(function(ds) {

        var entity = ds.entities.getById('path');

        // viewer.trackedEntity = entity;

        entity.orientation =  new Cesium.VelocityOrientationProperty(entity.position);

        entity.position.setInterpolationOptions({
            interpolationDegree : 1,
            interpolationAlgorithm : Cesium.HermitePolynomialApproximation
          });    
    });

    }
}], 'toolbar');

Sandcastle.reset = function() {
    viewer.dataSources.removeAll();
    viewer.clock.clockRange = Cesium.ClockRange.UNBOUNDED;
    viewer.clock.clockStep = Cesium.ClockStep.SYSTEM_CLOCK;
};
//Sandcastle_End

这样飞行器将与轨迹对齐！