【GIS功能:相交分析】openlayers结合turf相交分析-航路预警demo

已被阅读 1646 次 | 文章分类:OpenLayers | 2021-07-07 00:02

openlayers是gis渲染引擎，turf.js是一个gis辅助工具-gis空间关系分析库，结合二者可以做很多空间分析工作，比如简单的点线是否相交，如果有类似航路预警的业务需求可以借鉴

1 核心代码思路

(1) 模拟航路线轨迹坐标，途径危险点坐标

(2) 渲染航路线图层

(3) 渲染途径的危险区域(点-有一定半径区域)

(4) 用轨迹点和危险点，利用turf做相交运算，获取几何分析结果

(5) 渲染预警结果图层，将几何结果处理成openlayers支持的features展示即可

2 效果

小白GIS

3 全部代码

其中引用的ol.js turf.js去官网下载即可 openlayers,turf

                                        
<!DOCTYPE html>
<html>
  <head>
    <title>openlayers结合turf相交分析-航路预警demo</title>
    <link rel="stylesheet" href="../../static/data/ol.css" type="text/css" />
    <script src="../../static/data/ol.js"></script>
    <script src="../../static/data/turf.js"></script>
    <style>
      .blingAnimation {
        height: 30px;
        width: 30px;
        border-radius: 25px;
        background: rgb(255, 0, 0);
        transform: scale(0.3);
        animation: myfirst 1s;
        animation-iteration-count: infinite;
        z-index: 200;
        border: solid 1px purple;
      }
      @keyframes myfirst {
        to {
          transform: scale(0.8);
          background: rgba(255, 0, 0, 0);
        }
      }
    </style>
  </head>
 
  <body>
    <div id="map" class="map"></div>
    <script>
      var map = new ol.Map({
        target: "map",
        layers: [
          new ol.layer.Tile({
            source: new ol.source.OSM()
          })
        ],
        view: new ol.View({
          center: [112, 34],
          zoom: 5,
          projection: "EPSG:4326"
        })
      })
      // 航路轨迹点
      let AirCoors = [
        [112, 34],
        [114, 35],
        [116, 37],
        [122, 41],
        [130, 43],
        [132, 44],
        [134, 34],
        [135, 34]
      ]
      // 危险点
      let ExtremeCoors = [
        [112, 34],
        [112.5, 36],
        [113, 34],
        [116, 34],
        [121, 44],
        [130.232, 43],
        [132, 34],
        [137, 45],
        [134, 34.99]
      ]
      let bufferArr = []
        renderAirRoute()
        renderExtremeElement()
        handleAnalyze()
      // 渲染航路
      function renderAirRoute() {
        let feature = new ol.Feature({
          geometry: new ol.geom.LineString(AirCoors)
        })
        let style = new ol.style.Style({
          stroke: new ol.style.Stroke({
            //边界样式
            color: "blue",
            width: 5,
            lineDash: [1, 2, 3, 4, 5, 6]
          })
        })
        feature.setStyle(style)
        // 创建source对象
        var airRouteSource = new ol.source.Vector({
          features: [feature]
        })
        // 创建layer对象
        var airRouteLayer = new ol.layer.Vector({
          source: airRouteSource,
          zIndex: 10
        })
        //将layer添加到map
        map.addLayer(airRouteLayer)
      }
      // 渲染危险点
      function renderExtremeElement() {
        // 创建source对象
        let extremeElementSource = new ol.source.Vector({
          features: []
        })
        // 创建layer对象
        let extremeElementLayer = new ol.layer.Vector({
          source: extremeElementSource,
          zIndex: 10,
          style:new ol.style.Style({
            image: new ol.style.Circle({
                radius: 10,
                fill: new ol.style.Fill({
                    color: 'orange'
                })
            })
          })
        })
        //将layer添加到map
        map.addLayer(extremeElementLayer)
        // 创建feature 对象
        let pointFeature = new ol.Feature({
          geometry: new ol.geom.MultiPoint(ExtremeCoors)
        })
        extremeElementSource.addFeature(pointFeature)
      }
      // turf分析
      function handleAnalyze() {
        let turfLine = turf.lineString(AirCoors)
        ExtremeCoors.forEach(function(coor) {
          let turfCircle = turf.circle(coor, 50) //半径单位是km
          let iScross = turf.booleanCrosses(turfLine, turfCircle)
          if (iScross) {
            // renderBufferResult(coor)
            createBlingOverlay(coor)
          }
        })
      }
      // 创建预警结果图层
      function createBlingOverlay(coor) {
        let dom = document.createElement("div")
        dom.classList.add("blingAnimation")
        var point_overlay = new ol.Overlay({
          //定义为全局变量
          element: dom,
          positioning: "center-center"
        })
        map.addOverlay(point_overlay)
        point_overlay.setPosition(coor)
      }
      // 渲染危险buffer区域
      function renderBufferResult(coor) {
        let olCircle = new ol.geom.Circle(coor, 1)
        let feature = new ol.Feature({
          geometry: olCircle
          // labelPoint: new ol.geom.Point([center_x, center_y]),
          // name: "333"
        })
        var source = new ol.source.Vector({
          features: [feature]
        })
        // 创建layer对象
        var layer = new ol.layer.Vector({
          source: source,
          zIndex: 9
        })
        //将layer添加到map
        map.addLayer(layer)
        let style = new ol.style.Style({
          stroke: new ol.style.Stroke({
            color: "purple",
            width: 3
          }),
          fill: new ol.style.Fill({
            color: "red"
          })
        })
        let style1 = new ol.style.Style({
          stroke: new ol.style.Stroke({
            color: "purple",
            width: 1
          }),
          fill: new ol.style.Fill({
            color: "orange"
          })
        })
        let setIntervalId = setInterval(() => {
          layer.setStyle(style)
        }, 500)
        let setIntervalId1 = setInterval(() => {
          layer.setStyle(style1)
        }, 1000)
      }
    </script>
  </body>
</html>

多边形和多边形相交可以参考空间分析-相交篇

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