在2D地图中，如何获取鼠标位置的地形高度

Question

我在2D模式下使用铯。这是我用来获取鼠标位置的地形高度的代码：

cartographic = Cesium.Ellipsoid.WGS84.cartesianToCartographic( position );
var longitudeString = Cesium.Math.toDegrees(cartographic.longitude).toFixed(10);
var latitudeString = Cesium.Math.toDegrees(cartographic.latitude).toFixed(10);          
mapPointerLatitude = latitudeString.slice(-15);
mapPointerLongitude = longitudeString.slice(-15);
var tempHeight = cartographic.height;
if( tempHeight < 0 ) tempHeight = 0; 
mapPointerHeight = tempHeight.toFixed(2);

position来自Cesium.ScreenSpaceEventType.MOUSE_MOVE事件：

if ( mapStyle === '2D' ) {
var position = viewer.camera.pickEllipsoid(movement.endPosition, scene.globe.ellipsoid);
if (position) {
return position;
} 
}
if ( mapStyle === '3D' ) {
var ray = viewer.camera.getPickRay(movement.endPosition);
var position = viewer.scene.globe.pick(ray, viewer.scene);
if (Cesium.defined(position)) {
return position;
} 
}

当地图处于3D模式(Cesium.SceneMode.SCENE3D(时，我在tempHeight中具有高度值，但当地图处于Cesium.SceneMode.SCENE2D时，该值始终为零。我做错了什么？

编辑不知道这是否是最好的方法，但我可以将代码放入其中：

cartographic = Cesium.Ellipsoid.WGS84.cartesianToCartographic( position );
var positions = [ cartographic ];
var promise = Cesium.sampleTerrain(terrainProvider, 11, positions);
Cesium.when(promise, function( updatedPositions ) {
// PUT ALL HERE
});

Answer 1

您实际上可以尝试Cesium.sampleTerrainMostDetailed以获得更精确的海拔高度。

// Query the terrain height of two Cartographic positions
const terrainProvider = Cesium.createWorldTerrain();
const positions = [
Cesium.Cartographic.fromDegrees(86.925145, 27.988257),
Cesium.Cartographic.fromDegrees(87.0, 28.0)
];
Cesium.sampleTerrainMostDetailed(terrainProvider, positions).then((updatedPositions) => {
// positions[0].height and positions[1].height have been updated.
// updatedPositions is just a reference to positions.
})

https://cesium.com/learn/cesiumjs/ref-doc/global.html?classFilter=sample#sampleTerrainMostDetailed