路徑分析本人是基於高德來做的，調用百度的大致過程類似，只是修改座標轉換的方法，此處就不放出基於百度的路徑分析了；
先說下此功能的思路，由於高德的座標系是國測局的，而cesium的座標系是wgs84的，故要對偏差進行處理，處理之後再進行模擬；
這裏調用的是駕駛車輛的路徑規劃，高德支持步行、駕車等多種路徑規劃；
一般高德一次性會計算出多條線路，此處爲了展示方便，取第一條線路來進行展示。此處計算的是兩點之間的用時最少的路線。
高德計算兩點之間的路徑後，會提供多種選擇，比如 用時最少、距離最短、躲避擁堵、避免收費等，多種結果的選擇爲項目的開發提供了極大的便利，並提供了豐富的效果展示；
大致步驟：
1、先在圖上拾取兩點座標，對座標進行偏差處理；
2、傳入高德服務接口，獲取路徑結果。
3、對路徑結果進行二次偏差處理。
4、展示路線，及模擬車輛運動，模擬沿此路徑跑完全程。
其中車輛的模擬運動支持設置跑完全程的時間，及車輛移動的速度；
代碼如下：如果你是個新手，可以好好感悟下我的代碼，相信你會有所收穫的！
-
function getCatesian3FromPX(px, viewer, entity) { -
var pick = viewer.scene.pick(px); -
var cartesian; -
var drillPick = viewer.scene.drillPick(px); -
var truePick = null; -
if (entity) { -
for (var i = 0; i < drillPick.length; i++) { -
if (drillPick[i].id._id != entity.id) { -
truePick = drillPick[i].id; -
break; -
} -
} -
} else { -
truePick = pick; -
} -
if (viewer.scene.pickPositionSupported && Cesium.defined(truePick)) { -
cartesian = viewer.scene.pickPosition(px); -
} else { -
var ray = viewer.camera.getPickRay(px); -
if (!ray) return; -
cartesian = viewer.scene.globe.pick(ray, viewer.scene); -
} -
return cartesian; -
} -
function cartesianToLnglat(cartesian, isToWgs84) { -
if (!cartesian) return; -
var ellipsoid = viewer.scene.globe.ellipsoid; -
var lnglat = ellipsoid.cartesianToCartographic(cartesian); -
//var cartographic = Cesium.Cartographic.fromCartesian(cartesian); -
if (isToWgs84) { -
var lat = Cesium.Math.toDegrees(lnglat.latitude); -
var lng = Cesium.Math.toDegrees(lnglat.longitude); -
var hei = lnglat.height; -
return [lng, lat, hei]; -
} else { -
return [lnglat.longitude, lnglat.latitude, lnglat.height]; -
} -
} -
function lnglatToCartesian(lnglat) { //經緯度轉世界座標 [101,40] -
if (!lnglat) return null; -
return Cesium.Cartesian3.fromDegrees(lnglat[0], lnglat[1], lnglat[2] || 0); -
} -
function lnglatArrToCartesianArr(lnglatArr) { -
if (!lnglatArr) return []; -
var arr = []; -
for (var i = 0; i < lnglatArr.length; i++) { -
arr.push(lnglatToCartesian(lnglatArr[i])); -
} -
return arr; -
} -
var viewer = new Cesium.Viewer('map', { -
imageryProvider: new Cesium.ArcGisMapServerImageryProvider({ -
url: "https://services.arcgisonline.com/ArcGIS/rest/services/World_Imagery/MapServer" -
}), -
terrainProvider: new Cesium.CesiumTerrainProvider({ //加載火星在線地形 -
url: "http://data.marsgis.cn/terrain" -
}) -
}); -
class searchRoute { -
constructor(start, end) { -
this.startP = start; -
this.endP = end; -
} -
start(opt) { -
var startP = wgs2gcj(this.startP); -
var endP = wgs2gcj(this.endP); -
$.ajax({ -
url: "http://restapi.amap.com/v3/direction/driving", -
type: "GET", -
dataType: "jsonp", -
timeout: "5000", -
contentType: "application/json;utf-8", -
data: { -
"output": "json", -
"extensions": "all", -
"key": "你的key", -
"origin": startP[0] + "," + startP[1], -
"destination": endP[0] + "," + endP[1], -
"strategy": opt.strategy || 10 -
}, -
success: function(json) { -
// 由於線涉及座標較多 此處返回的座標 未轉爲wgs84 -
var data = ""; -
if (!json || !json.route || !json.route.paths) { -
data = ""; -
} else { -
data = json.route.paths; -
} -
opt.callback(data); -
}, -
error: function(data) {} -
}); -
} -
} -
var handler = new Cesium.ScreenSpaceEventHandler(viewer.scene.canvas); -
var isClickAgain = false; -
var start = null; -
var entd = null; -
handler.setInputAction(function(evt) { //單機開始繪製 -
var pick = viewer.scene.pick(evt.position); -
var cartesian = getCatesian3FromPX(evt.position, viewer); -
if (!isClickAgain) { -
isClickAgain = true; -
start = viewer.entities.add({ -
name: "圖標點", -
position: cartesian, -
billboard: { -
image: 'mark4.png', -
scale: 1, -
horizontalOrigin: Cesium.HorizontalOrigin.CENTER, -
verticalOrigin: Cesium.VerticalOrigin.BOTTOM -
} -
}); -
return; -
} -
if (isClickAgain) { -
end = viewer.entities.add({ -
name: "圖標點", -
position: cartesian, -
billboard: { -
image: 'mark2.png', -
scale: 1, -
horizontalOrigin: Cesium.HorizontalOrigin.CENTER, -
verticalOrigin: Cesium.VerticalOrigin.BOTTOM -
} -
}); -
showRes(start.position.getValue(), end.position.getValue()); -
handler.destroy(); -
} -
}, Cesium.ScreenSpaceEventType.LEFT_CLICK); -
function showRes(start, end) { -
if (!start || !end) return; -
var startp = cartesianToLnglat(start, true); -
var endP = cartesianToLnglat(end, true); -
var search = new searchRoute([startp[0], startp[1]], [endP[0], endP[1]]); -
search.start({ -
strategy: 11, -
callback: function(data) { -
addRouteLine(data[0]); -
} -
}) -
} -
function addRouteLine(res) { -
var arr = []; -
var steps = res.steps; -
for (var i = 0; i < steps.length; i++) { -
var item = steps[i]; -
var positionStr = item.polyline; -
var strArr = positionStr.split(";"); -
for (var z = 0; z < strArr.length; z++) { -
var item2 = strArr[z]; -
var strArr2 = item2.split(","); -
var p = gcj2wgs(strArr2); -
arr.push(p); -
} -
} -
var cartesians = lnglatArrToCartesianArr(arr); -
var line = viewer.entities.add({ -
polyline: { -
positions: cartesians, -
clampToGround: true, -
material: Cesium.Color.RED.withAlpha(1), -
width: 3 -
} -
}); -
moveOnRoute(line); -
} -
//汽車移動========================= -
var qicheModel = null; -
function moveOnRoute(lineEntity) { -
if (!lineEntity) return; -
var positions = lineEntity.polyline.positions.getValue(); -
if (!positions) return; -
var allDis = 0; -
for (var index = 0; index < positions.length - 1; index++) { -
var dis = Cesium.Cartesian3.distance(positions[index], positions[index + 1]); -
allDis += dis; -
} -
var playTime = 100; -
var v = allDis / playTime; -
var startTime = viewer.clock.currentTime; -
var endTime = Cesium.JulianDate.addSeconds(startTime, playTime, new Cesium.JulianDate()); -
var property = new Cesium.SampledPositionProperty(); -
var t = 0; -
for (var i = 1; i < positions.length; i++) { -
if (i == 1) { -
property.addSample(startTime, positions[0]); -
} -
var dis = Cesium.Cartesian3.distance(positions[i], positions[i - 1]); -
var time = dis / v + t; -
var julianDate = Cesium.JulianDate.addSeconds(startTime, time, new Cesium.JulianDate()); -
property.addSample(julianDate, positions[i]); -
t += dis / v; -
} -
if (qicheModel) { -
window.viewer.entities.remove(qicheModel); -
qicheModel = null; -
} -
qicheModel = viewer.entities.add({ -
position: property, -
orientation: new Cesium.VelocityOrientationProperty(property), -
model: { -
uri: "car.glb", -
scale: 30 -
} -
}); -
viewer.clock.currentTime = startTime; -
viewer.clock.multiplier = 1; -
viewer.clock.shouldAnimate = true; -
viewer.clock.stopTime = endTime; -
} -
//座標轉換================================== -
var x_PI = 3.14159265358979324 * 3000.0 / 180.0; -
var PI = 3.1415926535897932384626; -
var a = 6378245.0; -
var ee = 0.00669342162296594323; -
function transformWD(lng, lat) { -
var ret = -100.0 + 2.0 * lng + 3.0 * lat + 0.2 * lat * lat + 0.1 * lng * lat + 0.2 * Math.sqrt(Math.abs(lng)); -
ret += (20.0 * Math.sin(6.0 * lng * PI) + 20.0 * Math.sin(2.0 * lng * PI)) * 2.0 / 3.0; -
ret += (20.0 * Math.sin(lat * PI) + 40.0 * Math.sin(lat / 3.0 * PI)) * 2.0 / 3.0; -
ret += (160.0 * Math.sin(lat / 12.0 * PI) + 320 * Math.sin(lat * PI / 30.0)) * 2.0 / 3.0; -
return ret; -
} -
function transformJD(lng, lat) { -
var ret = 300.0 + lng + 2.0 * lat + 0.1 * lng * lng + 0.1 * lng * lat + 0.1 * Math.sqrt(Math.abs(lng)); -
ret += (20.0 * Math.sin(6.0 * lng * PI) + 20.0 * Math.sin(2.0 * lng * PI)) * 2.0 / 3.0; -
ret += (20.0 * Math.sin(lng * PI) + 40.0 * Math.sin(lng / 3.0 * PI)) * 2.0 / 3.0; -
ret += (150.0 * Math.sin(lng / 12.0 * PI) + 300.0 * Math.sin(lng / 30.0 * PI)) * 2.0 / 3.0; -
return ret; -
} -
function wgs2gcj(arrdata) { -
var lng = Number(arrdata[0]); -
var lat = Number(arrdata[1]); -
var dlat = transformWD(lng - 105.0, lat - 35.0); -
var dlng = transformJD(lng - 105.0, lat - 35.0); -
var radlat = lat / 180.0 * PI; -
var magic = Math.sin(radlat); -
magic = 1 - ee * magic * magic; -
var sqrtmagic = Math.sqrt(magic); -
dlat = dlat * 180.0 / (a * (1 - ee) / (magic * sqrtmagic) * PI); -
dlng = dlng * 180.0 / (a / sqrtmagic * Math.cos(radlat) * PI); -
var mglat = lat + dlat; -
var mglng = lng + dlng; -
mglng = Number(mglng.toFixed(6)); -
mglat = Number(mglat.toFixed(6)); -
return [mglng, mglat]; -
}; -
function gcj2wgs(arrdata) { -
var lng = Number(arrdata[0]); -
var lat = Number(arrdata[1]); -
var dlat = transformWD(lng - 105.0, lat - 35.0); -
var dlng = transformJD(lng - 105.0, lat - 35.0); -
var radlat = lat / 180.0 * PI; -
var magic = Math.sin(radlat); -
magic = 1 - ee * magic * magic; -
var sqrtmagic = Math.sqrt(magic); -
dlat = dlat * 180.0 / (a * (1 - ee) / (magic * sqrtmagic) * PI); -
dlng = dlng * 180.0 / (a / sqrtmagic * Math.cos(radlat) * PI); -
var mglat = lat + dlat; -
var mglng = lng + dlng; -
var jd = lng * 2 - mglng; -
var wd = lat * 2 - mglat; -
jd = Number(jd.toFixed(6)); -
wd = Number(wd.toFixed(6)); -
return [jd, wd]; -
}