cesium编程入门绘制形状

Posted 2020-10-20 伐罗密

通过Entity添加形状

先来看一个添加立方体的例子

var viewer = new Cesium.Viewer(‘cesiumContainer‘);
var redBox = **viewer.entities.add**({
  name : ‘Red box with black outline‘,
  position: Cesium.Cartesian3.fromDegrees(-107.0, 40.0, 300000.0),
  box : {
    dimensions : new Cesium.Cartesian3(400000.0, 300000.0, 500000.0),
    material : Cesium.Color.RED.withAlpha(0.5),
    outline : true,
    outlineColor : Cesium.Color.BLACK
  }
});

viewer.zoomTo(viewer.entities);

效果如图：

通过CZML添加

通过CZML也可以添加几何形状，而且CZML还可以描述动画(现在先有个印象，动画以后介绍)

先来看看官网上的说明，CZML是一种JSON格式的字符串，用于描述与时间有关的动画场景，CZML包含点、线、地标、模型、和其他的一些图形元素，并指明了这些元素如何随时间而变化。某种程度上说, Cesium 和 CZML的关系就像 Google Earth 和 KML。

var czml = [{
    "id" : "document",
    "name" : "box",
    "version" : "1.0"
},{
    "id" : "shape2",
    "name" : "Red box with black outline",
    "position" : {
        "cartographicDegrees" : [-107.0, 40.0, 300000.0]
    },
    "box" : {
        "dimensions" : {
            "cartesian": [400000.0, 300000.0, 500000.0]
        },
        "material" : {
            "solidColor" : {
                "color" : {
                    "rgba" : [255, 0, 0, 128]
                }
            }
        },
        "outline" : true,
        "outlineColor" : {
            "rgba" : [0, 0, 0, 255]
        }
    }
}];

var viewer = new Cesium.Viewer(‘cesiumContainer‘);
var dataSourcePromise = Cesium.CzmlDataSource.load(czml);
viewer.dataSources.add(dataSourcePromise);
viewer.zoomTo(dataSourcePromise);

可以看到单个的形状和Entity的描述基本一致，只不过是使用JSON语法来描述，关于形状描述可以参考官方API，下一节列出形状的相关信息

形状相关描述

下表来自于官方网站，但是连接改为本地链接了

Point		entity.point - Reference Build/Documentation
Boxes		entity.box - Code example - Reference Build/Documentation
Circles and Ellipses		entity.ellipse - Code example - Reference Build/Documentation
Corridor		entity.corridor - Code example - Reference Build/Documentation
Cylinder and Cones		entity.cylinder - Code example - Reference Build/Documentation
Polygons		entity.polygon - Code example - Reference Build/Documentation
Polylines		entity.polyline - Code example - Reference Build/Documentation
Polyline Volumes		entity.polylineVolume - Code example - Reference Build/Documentation
Rectangles		entity.rectangle - Code example - Reference Build/Documentation
Spheres and Ellipsoids		entity.ellipsoid - Code example - Reference Build/Documentation
Walls		entity.wall - Code example - Reference Build/Documentation