1.话不多说，先展示
视频：淹没分析
2.设计思路
绘制点移动绘制多个点会形成一个面，右键完成绘制，点击开始淹没分析水位会进行设定速度、设定高度的上升，有动画效果。项目中使用了自己的token和高程数据，需要使用者替换自己的token和高程。
3.具体代码
<template>
<div id="cesiumContainer">
<div id="toolbar">
<el-form style="width: 400px">
<el-form-item>
<el-button type="primary" @click="drawExtent">绘制</el-button>
<el-button type="primary" @click="induationAnalysis">淹没分析</el-button>
<el-button type="primary" @click="clearAllEntities">清除</el-button>
</el-form-item>
</el-form>
</div>
</div>
</template>
<script setup>
import * as turf from '@turf/turf';
import { onMounted, onUnmounted } from "vue";
let viewer;
let activeShapePoints = [];
let floatingPoint = undefined;
let activeShape = undefined;
let handler = undefined;
let isDraw = false;
let maxWaterHeight = 2500;
let minWaterHeight = 0;
let warningWaterHeight = 0; // 预警高度
let waterHeight = 0;
let speed = "3.0";
let waterHeightTimmer = 0;
let tempEntities = [];
const drawExtent = () => {
viewer.scene.globe.depthTestAgainstTerrain = true; // 开启深度检测
handler = new Cesium.ScreenSpaceEventHandler(viewer.canvas);
handler.setInputAction((event) => {
const earthPosition = viewer.scene.pickPosition(event.position);
if (Cesium.defined(earthPosition)) {
if (activeShapePoints.length === 0) {
floatingPoint = createPoint(earthPosition);
activeShapePoints.push(earthPosition);
const dynamicPositions = new Cesium.CallbackProperty(() => {
return new Cesium.PolygonHierarchy(activeShapePoints);
}, false);
activeShape = drawShape(dynamicPositions, Cesium.Color.fromBytes(64, 157, 253, 50));
}
activeShapePoints.push(earthPosition);
tempEntities.push(createPoint(earthPosition));
}
}, Cesium.ScreenSpaceEventType.LEFT_CLICK);
handler.setInputAction((event) => {
if (Cesium.defined(floatingPoint)) {
const newPosition = viewer.scene.pickPosition(event.endPosition);
if (Cesium.defined(newPosition)) {
floatingPoint.position.setValue(newPosition);
activeShapePoints.pop();
activeShapePoints.push(newPosition);
}
}
}, Cesium.ScreenSpaceEventType.MOUSE_MOVE);
handler.setInputAction(() => {
activeShapePoints.pop();
if (activeShapePoints.length < 3) return;
tempEntities.push(drawPolyline(activeShapePoints));
let ploy = drawShape(activeShapePoints, Cesium.Color.fromBytes(64, 157, 253, 20));
tempEntities.push(ploy);
getAreaHeight(activeShapePoints);
viewer.entities.remove(floatingPoint);
viewer.entities.remove(activeShape);
floatingPoint = undefined;
activeShape = undefined;
handler.destroy();// 关闭事件句柄
handler = null;
}, Cesium.ScreenSpaceEventType.RIGHT_CLICK);
}
const getAreaHeight = (positions) => {
let startP = positions[0];
let endP = positions[positions.length - 1];
if (startP.x != endP.x && startP.y != endP.y && startP.z != endP.z) {
positions.push(positions[0]);
}
const tempPoints = [];
for (let i = 0; i < positions.length; i++) {
let ellipsoid = viewer.scene.globe.ellipsoid;
let cartographic = ellipsoid.cartesianToCartographic(positions[i]);
let lat = Cesium.Math.toDegrees(cartographic.latitude);
let lng = Cesium.Math.toDegrees(cartographic.longitude);
tempPoints.push([lng, lat]);
}
let line = turf.lineString(tempPoints);
let chunk = turf.lineChunk(line, 10, { units: 'meters' });
const tempArray = [];
chunk.features.forEach(f => {
f.geometry.coordinates.forEach(c => {
tempArray.push(Cesium.Cartographic.fromDegrees(c[0], c[1]));
})
})
let promise = Cesium.sampleTerrainMostDetailed(viewer.terrainProvider, tempArray);
promise.then((updatedPositions) => {
const max = Math.max.apply(Math, updatedPositions.map(item => { return item.height }))
const min = Math.min.apply(Math, updatedPositions.map(item => { return item.height }))
waterHeight = Math.ceil(min);
warningWaterHeight = (max + min) / 2;
minWaterHeight = Math.ceil(min);
maxWaterHeight = Math.ceil(max);
isDraw = !isDraw; // 禁用绘制按钮
})
}
const createPoint = (worldPosition) => {
const point = viewer.entities.add({
position: worldPosition,
point: {
color: Cesium.Color.SKYBLUE,
pixelSize: 5,
heightReference: Cesium.HeightReference.CLAMP_TO_GROUND,
},
});
return point;
}
const drawShape = (positionData, mat) => {
let shape = viewer.entities.add({
polygon: {
hierarchy: positionData,
material: mat,
outline: true,
outlineColor: Cesium.Color.SKYBLUE,
outlineWidth: 4,
}
});
return shape;
}
const drawPolyline = (positions) => {
if (positions.length < 1) return;
let startP = positions[0];
let endP = positions[positions.length - 1];
if (startP.x != endP.x && startP.y != endP.y && startP.z != endP.z) {
positions.push(positions[0]);
}
return viewer.entities.add({
name: 'polyline',
polyline: {
positions: positions,
width: 2.0,
material: Cesium.Color.SKYBLUE,
clampToGround: true
}
})
}
const induationAnalysis = () => {
if (Number(warningWaterHeight) < Number(minWaterHeight) || Number(warningWaterHeight) > Number(maxWaterHeight)) {
alert('预警高度必须在最小高度和最大高度之间');
return;
}
let shape = viewer.entities.add({
polygon: {
hierarchy: activeShapePoints,
// material: Cesium.Color.fromBytes(64, 157, 253, 20),
material: Cesium.Color.RED.withAlpha(0.2),
extrudedHeight: Number(warningWaterHeight),
outline: true,
outlineColor: Cesium.Color.RED,
outlineWidth: 4,
// perPositionHeight: true
}
});
tempEntities.push(shape);
waterHeight = Number(minWaterHeight);
const entity = viewer.entities.add({
polygon: {
hierarchy: activeShapePoints,
extrudedHeight: new Cesium.CallbackProperty(() => {
return waterHeight
}, false),
material: Cesium.Color.fromBytes(64, 157, 253, 150),
}
});
tempEntities.push(entity);
waterHeightTimmer = setInterval(() => {
waterHeight += Number(speed);
let l = speed.split('.').length > 1 ? speed.split('.')[1].length : 0;
waterHeight = Number(waterHeight.toFixed(l));
maxWaterHeight = Number(maxWaterHeight);
minWaterHeight = Number(minWaterHeight);
if (waterHeight > maxWaterHeight || waterHeight < minWaterHeight) {
clearInterval(waterHeightTimmer);
waterHeight = waterHeight > maxWaterHeight ? maxWaterHeight : minWaterHeight;
}
}, 100)
}
const clearAllEntities = () => {
if (waterHeightTimmer) {
clearInterval(waterHeightTimmer);
}
const length = tempEntities.length;
for (let i = 0; i < length; i++) {
viewer.entities.remove(tempEntities[i]);
}
tempEntities = [];
activeShapePoints = [];
maxWaterHeight = 200;
minWaterHeight = 0;
warningWaterHeight = 0;
isDraw = !isDraw;
floatingPoint = undefined;
activeShape = undefined;
if (handler) {
handler.destroy();
handler = undefined;
}
}
const defaultPos = {
destination: Cesium.Cartesian3.fromDegrees(112.536806, 37.851355, 900),
orientation: {
heading: Cesium.Math.toRadians(299.7957386132123),
pitch: Cesium.Math.toRadians(-10.012383459541422),
roll: 0.001963990089065944,
},
}
onMounted(() => {
Cesium.Ion.defaultAccessToken = '替换自己的token';
viewer = new Cesium.Viewer('cesiumContainer', {
animation: false, // 是否显示动画控件
baseLayerPicker: false, // 是否显示图层选择控件
geocoder: false, // 是否显示地名查找控件
timeline: false, // 是否显示时间线控件
sceneModePicker: false, // 是否显示投影方式控件
navigationHelpButton: false, // 是否显示帮助信息控件
infoBox: false, // 是否显示点击要素之后显示的信息
fullscreenButton: false, // 是否显示全屏按钮
selectionIndicator: false, // 是否显示选中指示框
scene3DOnly: true,
homeButton: false
})
viewer.terrainProvider = new Cesium.CesiumTerrainProvider({
url: '替换自己高程地址',
});
viewer.camera.setView(defaultPos);
});
onUnmounted(() => {
clearAllEntities();
})
</script>
<style>
html,
body,
#app,
#cesiumContainer {
width: 100%;
height: 100%;
padding: 0;
margin: 0;
overflow: hidden;
}
#toolbar {
background: rgba(42, 42, 42, 0.8);
position: absolute;
margin: 18px;
padding: 18px;
border-radius: 5px;
z-index: 999;
color: #fff;
}
</style>
