LeaFlet学习之结合turf.js生成简单的等值线demo

本文主要结合turf.js生成等值线俺，进行展示效
一、放张图：
二、全部源码
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    <title>等值线的生成</title>
    <link href="Script/leaflet/leaflet.css" rel="stylesheet" />
    <style>
        #map
        {
            height: 2000px;
             1500px;
        }
    </style>
    <script src="Script/leaflet/leaflet.js"></script>
    <script src="Script/leaflet/leaflet.ChineseTmsProviders.js"></script>
    <script src='https://npmcdn.com/@turf/turf/turf.min.js'></script>
</head>
<body>
    <div id="map"></div>
    
</body>
    <script>
        var normalm = L.tileLayer.chinaProvider('TianDiTu.Normal.Map', {
            maxZoom: 18,
            minZoom: 1
        }),
            normala = L.tileLayer.chinaProvider('TianDiTu.Normal.Annotion', {
                maxZoom: 18,
                minZoom: 1
            }),
            imgm = L.tileLayer.chinaProvider('TianDiTu.Satellite.Map', {
                maxZoom: 18,
                minZoom: 1
            }),
            imga = L.tileLayer.chinaProvider('TianDiTu.Satellite.Annotion', {
                maxZoom: 18,
                minZoom: 1
            });

        var normal = L.layerGroup([normalm, normala]);
        image = L.layerGroup([imgm, imga]);

        var baseLayers = {
            "地图": normal,
            "影像": image,
        }

        var overlayLayers = {
            "图": normal,
            "像": image,
        }

        var map = L.map("map", {
            center: [31.59, 120.29],
            zoom: 12,
            layers: [normal],
            zoomControl: false

        });
        // 创建等值线区域
        var extent = [0, 30, 20, 50];
        var cellWidth = 100;
        var pointGrid = turf.pointGrid(extent, cellWidth, { units: 'miles' });

        for (var i = 0; i < pointGrid.features.length; i++) {
            pointGrid.features[i].properties.temperature = Math.random() * 10;
        }
        console.log(pointGrid.features.length);
        //等值线的级数
        var breaks = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];

        var lines = turf.isolines(pointGrid, breaks, { zProperty: 'temperature' });
        //设置颜色
        var myStyle = {
            "color": "#ff7800",
            "weight": 5,
            "opacity": 0.65
        };
        //进行平滑处理
            var _lFeatures = lines.features;
            for(var i=0;i<_lFeatures.length;i++){
                var _coords = _lFeatures[i].geometry.coordinates;
                var _lCoords = [];
                for(var j=0;j<_coords.length;j++){
                    var _coord = _coords[j];
                    var line = turf.lineString(_coord);
                    var curved = turf.bezierSpline(line);
                    _lCoords.push(curved.geometry.coordinates);
                }
                _lFeatures[i].geometry.coordinates = _lCoords;
            }
        //geojson数据读取
        L.geoJSON(lines, {
            style: myStyle
        }).addTo(map);
    </script>
</html>
三、总结
这里是等值线，可不是等高线，等高线不会相交，等值线可能相交，数据平滑参考牛老师ol4的等值线效果。