[cesium]地形挖⽅分析效果
windowsmediaplayer是什么github上看到⼀个挖⽅的插件，准备改造完善填挖⽅功能，引⼊即可使⽤。
本地⽰例代码
/**
* 创建⽅量分析
* @param {*} options
*/
createCutVolumeAnalysis(options) {
options = options || {}
if (this._viewer && options) {
var $this = this;
$this.drawWallGraphics({ //绘制贴地线返回positions
callback: function (wall, wallobj) {
var _cutVolumeAnalysis = new CutVolumeAnalysis({
positions:
$ansformWGS84ArrayToCartesianArray(wall, 100),
that: $this
})
if (typeof options.callback === 'function') {
options.callback(_cutVolumeAnalysis)
}
}
})
}
}
/**
* ⽅量分析
* @param {*} params
*/
function CutVolumeAnalysis(params) {
if (params && params.positions && params.that) {
var that = params.that, positions = params.positions
, _debugShowSubTriangles = true, $this = this;
computeCutVolume()
}
/
**
* 计算多边形的重⼼点
* @param {*} positions
*/
function computeCentroidOfPolygon(positions) {
var x = [];
var y = [];
for (var i = 0; i < positions.length; i++) {
var cartographic = Cesium.Cartographic.fromCartesian(positions[i]);
x.push(cartographic.longitude);
y.push(cartographic.latitude);
}
var x0 = 0.0, y0 = 0.0, x1 = 0.0, y1 = 0.0;
var signedArea = 0.0;
var a = 0.0;
var centroidx = 0.0, centroidy = 0.0;
for (i = 0; i < positions.length; i++) {
x0 = x[i];
y0 = y[i];
if (i == positions.length - 1) {
x1 = x[0];
y1 = y[0];
} el {
x1 = x[i + 1];
y1 = y[i + 1];
}
a = x0 * y1 - x1 * y0;
signedArea += a;
centroidx += (x0 + x1) * a;
centroidy += (y0 + y1) * a;
}
signedArea *= 0.5;
centroidx /= (6.0 * signedArea);
centroidy /= (6.0 * signedArea);
couples
return new Cesium.Cartographic(centroidx, centroidy);
}
/**
* 计算三⾓形的⾯积
* @param {*} pos15552
* @param {*} pos2
* @param {*} pos3
*/
function computeAreaOfTriangle(pos1, pos2, pos3) {
var a = Cesium.Cartesian3.distance(pos1, pos2);
var b = Cesium.Cartesian3.distance(pos2, pos3);
var c = Cesium.Cartesian3.distance(pos3, pos1);
var S = (a + b + c) / 2;
return Math.sqrt(S * (S - a) * (S - b) * (S - c));
}
/**
* 计算⽅量
*/
function computeCutVolume() {
var tileAvailability = that._ainProvider.availability;
if (!tileAvailability) {
alert("未获取到地形")
return fal;
}
var maxLevel = 0;
var minHeight = 15000;
// 计算差值点
for (var i = 0; i < positions.length; i++) {
var cartographic = Cesium.Cartographic.fromCartesian(positions[i]);
var height = that._viewer.Height(cartographic);
if (minHeight > height)
minHeight = height;
var level = puteMaximumLevelAtPosition(cartographic);
if (maxLevel < level)
maxLevel = level;
}
assist是什么意思var granularity = Math.PI / Math.pow(2, 11);
granularity = granularity / (64);
var polygonGeometry = new Cesium.PolygonGeometry.fromPositions(
{
positions: positions,
vertexFormat: Cesium.PerInstanceColorAppearance.FLAT_VERTEX_FORMAT, granularity: granularity
}
);
//polygon subdivision
var geom = new ateGeometry(polygonGeometry);
var totalCutVolume = 0;
var maxHeight = 0;
var i0, i1, i2;
var height1, height2, height3;
var p1, p2, p3;
var bottomP1, bottomP2, bottomP3;英语在线翻译
country roadvar scratchCartesian = new Cesium.Cartesian3();
var cartographic;
var bottomArea;
var subTrianglePositions;
for (i = 0; i < geom.indices.length; i += 3) {
i0 = geom.indices[i];
i1 = geom.indices[i + 1];
i2 = geom.indices[i + 2];
subTrianglePositions = geom.attributes.position.values;
scratchCartesian.x = subTrianglePositions[i0 * 3];
scratchCartesian.y = subTrianglePositions[i0 * 3 + 1];
scratchCartesian.z = subTrianglePositions[i0 * 3 + 2];
cartographic = Cesium.Cartographic.fromCartesian(scratchCartesian);
height1 = that._viewer.Height(cartographic);
p1 = Cesium.Cartesian3.fromRadians(cartographic.longitude, cartographic.latitude, height1);
bottomP1 = Cesium.Cartesian3.fromRadians(cartographic.longitude, cartographic.latitude, 0);
if (maxHeight < height1)
maxHeight = height1;
scratchCartesian.x = subTrianglePositions[i1 * 3];regarding
scratchCartesian.y = subTrianglePositions[i1 * 3 + 1];
scratchCartesian.z = subTrianglePositions[i1 * 3 + 2];
cartographic = Cesium.Cartographic.fromCartesian(scratchCartesian);
height2 = that._viewer.Height(cartographic);
p2 = Cesium.Cartesian3.fromRadians(cartographic.longitude, cartographic.latitude, height2);
bottomP2 = Cesium.Cartesian3.fromRadians(cartographic.longitude, cartographic.latitude, 0);
if (maxHeight < height2)
maxHeight = height2;
scratchCartesian.x = subTrianglePositions[i2 * 3];
scratchCartesian.y = subTrianglePositions[i2 * 3 + 1];
scratchCartesian.z = subTrianglePositions[i2 * 3 + 2];
cartographic = Cesium.Cartographic.fromCartesian(scratchCartesian);
height3 = that._viewer.Height(cartographic);
p3 = Cesium.Cartesian3.fromRadians(cartographic.longitude, cartographic.latitude, height3);
bottomP3 = Cesium.Cartesian3.fromRadians(cartographic.longitude, cartographic.latitude, 0);
if (maxHeight < height3)
maxHeight = height3;
bottomArea = computeAreaOfTriangle(bottomP1, bottomP2, bottomP3);
totalCutVolume = totalCutVolume + bottomArea * (height1 - minHeight + height2 - minHeight + height3 - minHeight) / 3;
if (_debugShowSubTriangles) {
var positionsarr = [];
positionsarr.push(p1);
positionsarr.push(p2);
positionsarr.push(p3);
var drawingPolygon = {
polygon: {
hierarchy: {
positions: positionsarr
},
extrudedHeight: 0,
perPositionHeight: true,
material: Cesium.Color.fromRandom().withAlpha(0.5),
房产税入什么科目outline: true,
cloTop: true,
cloBottom: true,
outlineColor: Cesium.Color.WHITE,
outlineWidth: 2
}
};
that._ities.add(drawingPolygon);
}
}
var centroid = computeCentroidOfPolygon(positions);
$this._volumeLabel = that._ities.add({
position: Cesium.Cartesian3.fromRadians(centroid.longitude, centroid.latitude, maxHeight + 1000), label: {
text: 'Cut Volume ' + String() + 'm3'
}
});
return maxHeight;
};
}
在线调⽤⽰例
// 在引⼊的cesiumJS下⾯引⼊d3kit插件
<script src="zhangticcc.gitee.io/d3kit/d3kit.js"></script>
<script>
// 初始化 Cesium.Viewer
let viewer = new Cesium.Viewer("d3map");
// 初始化 d3kit
let d3kit = new Cesium.D3Kit(viewer)
// 开启世界地形
// 挖⽅⽰例在地形上绘制⼩块多边形切割多边形计算⾯积⽐较耗资源
</script>日语翻译考试
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