写在前面 ---- WebGIS开发基础之Leaflet
- GIS基本概念:GIS、Map、Layer、Feature、Geometry、Symbol、Data(Point、Polyline、Polygon)、Renderer、Scale、Project、Coordinates;
- GIS开发概述:架构模式、常用平台和SDK、二维三维
使用Leaflet开发常用功能
- 地图加载(底图类型、切换):
- 地图操作(缩放、平移、定位/书签、动画):
- 图层管理(加载、移除、调整顺序):
- 要素标绘(点/聚簇、线、面,符号化/静态动态):
- 属性标注(字段可选、样式定制):
- 专题地图(点、线、面,渲染):
- 查询定位(属性查询、空间查询/周边搜索/缓冲区/面查点线面/点线查面、图属互查、综合查询):
- 信息窗口(入口、Popup、定制):
- 坐标转换():
- 空间运算(长度面积测量、点取坐标、缓冲区、相交包含关系):
- 动态监控(固定点状态切换、车辆监控):
<link rel="stylesheet" type="text/css" href="./lib/Flat-UI-master/dist/css/vendor/bootstrap/css/bootstrap.min.css" /> <link rel="stylesheet" href="./lib/Flat-UI-master/dist/css/flat-ui.min.css"><link rel="stylesheet" href="./lib/leaflet/leaflet.css">
<script src="./lib/Flat-UI-master/dist/js/vendor/jquery.min.js"></script><script src="./lib/Flat-UI-master/dist/js/flat-ui.js"></script><script src="./lib/leaflet/leaflet.js"></script><script src="./js/urlTemplate.js"></script>
const map = L.map("mapDiv", { crs: L.CRS.EPSG3857, //要使用的坐标参考系统,默认的坐标参考系,互联网地图主流坐标系 // crs: L.CRS.EPSG4326, //WGS 84坐标系,GPS默认坐标系 zoomControl: true, // minZoom: 1, attributionControl: true, }).setView([30.6268660000, 104.1528940000], 18);//定位在成都北纬N30°37′45.58″ 东经E104°09′1.44″ let Baselayer = L.tileLayer(urlTemplate.mapbox_Image, { maxZoom: 17, //最大视图 minZoom: 2, //最小视图 attribution: 'liuvigongzuoshi@foxmail.com © <a href="https://github.com/liuvigongzuoshi/WebGIS-for-learnning/tree/master/Leaflet_Demo">WebGIS-for-learnning</a>' }).addTo(map);const setLayer = (ele) => { map.removeLayer(Baselayer) if (ele == "mapbox_Image") { Baselayer = L.tileLayer(urlTemplate.mapbox_Image, { maxZoom: 17, minZoom: 2 }).addTo(map); } else if (ele == "mapbox_Vector") { Baselayer = L.tileLayer(urlTemplate.mapbox_Vector, { maxZoom: 17, // minZoom: 2 }).addTo(map); console.log(Baselayer) }}
//marker高亮显示库引用<link rel="stylesheet" href="./lib/leaflet.marker.highlight/leaflet.marker.highlight.css"><script src="./lib/leaflet.marker.highlight/leaflet.marker.highlight.js"></script>
let map; let Baselayer; // 使用H5 API定位 定位在当前位置 if (navigator.geolocation) { console.log('/* 地理位置服务可用 */') navigator.geolocation.getCurrentPosition(h5ApiSuccess, h5ApiError); } else { console.log('/* 地理位置服务不可用 */') mapInit([30.374558, 104.09144]);//指定一个数据 定位在成都北纬N30°37′45.58″ 东经E104°09′1.44″ }
const h5ApiSuccess = (position) => { var latitude = position.coords.latitude; //纬度 var longitude = position.coords.longitude; //经度 console.log('你的经度纬度分别为' + longitude + ',' + latitude + '。') return mapInit([latitude, longitude]); }; const h5ApiError = () => { console.log('/* 地理位置请求失败 */') mapInit([30.374558, 104.09144]);//指定一个数据 定位在成都北纬N30°37′45.58″ 东经E104°09′1.44″ };
const mapInit = (LatLng) => { map = L.map("mapDiv", { crs: L.CRS.EPSG3857, //要使用的坐标参考系统,默认的坐标参考系 // crs: L.CRS.EPSG4326, //国内的坐标参考系 zoomControl: true, // minZoom: 1, attributionControl: true, }).setView(LatLng, 18);//定位在当前位置 Baselayer = L.tileLayer(urlTemplate.mapbox_Image, { maxZoom: 17, //最大视图 minZoom: 2, //最小视图 attribution: 'liuvigongzuoshi@foxmail.com © <a href="https://github.com/liuvigongzuoshi/WebGIS-for-learnning/tree/master/Leaflet_Demo">WebGIS-for-learnning</a>' }).addTo(map); L.marker(LatLng, { highlight: "permanent" //永久高亮显示 }).addTo(map); }
- 更多了解geolocation对象,可参考MDN Web 文档
- 更多了解使用marker高亮显示,可参考leaflet.marker.highlight插件
- 基于Demo 1 利用eaflet封装好的H5定位API,定位到当前位置 Demo
map.setZoom(10, { // animate: false}) //设置地图缩放到
map.zoomIn() //图层往里进一个图层,放大//map.zoomOut() //图层往里出一个图层,缩小
map.panTo([37.91082, 128.73583], { animate: true}) //地图平移,默认就是true,将地图平移到给定的中心。如果新的中心点在屏幕内与现有的中心点不同则产生平移动作。
map.flyTo([36.52, 120.31]); // 点到点的抛物线动画,平移加缩放动画
注意:尽量避免setZoom()等地图缩放方法与flyTo、flyToBounds一起合用,因为这两类地图操作方法都有各自的缩放值,造成动画不流畅、不能定位到目的点。
map.flyToBounds(polygon.getBounds()); //getBounds(获取边界):返回地图视图的经纬度边界。 //飞到这个多变形区域上面,自动判断区域块的大小,合适缩放图层,将地图视图尽可能大地设定在给定的地理边界内。 let polygon = L.polygon( [[37, -109.05], [41, -109.03], [41, -102.05], [37, -102.04]], [40.774, -74.125], { color: 'green', fillColor: '#f03', fillOpacity: 0.5 }).addTo(map); //地图上绘制一个多形
map.fitBounds(polygon.getBounds()); //getBounds(获取边界):返回地图视图的经纬度边界。 //平移到一个区域上面,自动判断区域块的大小,合适缩放图层 let polygon = L.polygon( [[37, -109.05], [41, -109.03], [41, -102.05], [37, -102.04]], [40.774, -74.125], { color: 'green', fillColor: '#f03', fillOpacity: 0.5 }).addTo(map); //地图上绘制一个多边形
<link rel="stylesheet" type="text/css" href="./lib/Flat-UI-master/dist/css/vendor/bootstrap/css/bootstrap.min.css" /><link rel="stylesheet" href="./lib/Flat-UI-master/dist/css/flat-ui.min.css"><link rel="stylesheet" href="./lib/leaflet/leaflet.css">
<script src="./lib/Flat-UI-master/dist/js/vendor/jquery.min.js"></script><script src="./lib/Flat-UI-master/dist/js/flat-ui.js"></script><script src="./lib/leaflet/leaflet.js"></script><script src="./lib/esri-leaflet-v2.1.2/dist/esri-leaflet.js"></script> <!-- esri-leafleat插件 --><script src="./js/urlTemplate.js"></script>
let oMap = null; let oLayer = []; oMap = L.map('mapDiv', { crs: L.CRS.EPSG4326, zoomControl: false, minZoom: 7, attributionControl: false }).setView([29.59, 106.59], 12); //定位在重庆 oLayer.push(L.esri.tiledMapLayer({ url: urlTemplate.SYS_CQMap_IMG_MAPSERVER_PATH, maxZoom: 17, minZoom: 0, useCors: false, //是否浏览器在跨域的情况下使用GET请求。 }).addTo(oMap)); //加载第一个底图 oLayer.push(L.esri.tiledMapLayer({ url: urlTemplate.SYS_CQMap_IMG_LABEL_MAPSERVER_PATH, maxZoom: 17, minZoom: 0, useCors: false, }).addTo(oMap)); //加载第二个底图
const setLayer = (layerUrls, maxZoom) => { for (let i = 0; i < oLayer.length; i++) { oMap.removeLayer(oLayer[i]) //将图层在地图上移除 } oLayer = [] //制空数组 layerUrls.map((item) => { oLayer.push(L.esri.tiledMapLayer({ url: item, useCors: false, maxZoom: maxZoom, // 设置最大放大图层值 }).addTo(oMap)); }) }
不同的底图可能图层数不一样,就可能造成浏览器去请求不存在的图层,以及给用户展示出空白区域的不好体验,所以切换图层时候应注意设置最大及最小缩放值。
// 画一个circleconst circle = L.circle([36.52, 120.31], { color: 'green', //描边色 fillColor: '#f03', //填充色 fillOpacity: 0.5, //透明度 radius: 10000 //半径,单位米}).addTo(map);// 绑定一个提示标签circle.bindTooltip('我是个圆');
// 做一个makerconst marker = L.marker([36.52, 120.31]).addTo(map);// 绑定一个提示标签marker.bindTooltip('这是个Marker', { direction: 'left' }).openTooltip();//自定义一个makerconst greenIcon = L.icon({ iconUrl: './icon/logo.png', iconSize: [300, 79], // size of the icon popupAnchor: [0, -10] // point from which the popup should open relative to the iconAnchor});const oMarker = L.marker([36.52, 124.31], { icon: greenIcon }).addTo(map);// 绑定一个提示标签oMarker.bindTooltip('这是个自定义Marker', { direction: 'left', offset: [-150, 0] });
//画一根线const polyline = L.polyline([[45.51, -122.68], [37.77, -122.43], [34.04, -118.2]], { color: 'red' }).addTo(map);// 飞到这个线的位置// map.fitBounds(polyline.getBounds());
// 画一个polygonconst polygon = L.polygon([ [[37, -109.05], [41, -109.03], [41, -102.05], [37, -102.04]], // outer ring [[37.29, -108.58], [40.71, -108.58], [40.71, -102.50], [37.29, -102.50]] // hole], { color: 'green', fillColor: '#f03', fillOpacity: 0.5 }).addTo(map);// 绑定一个提示标签polygon.bindTooltip('this is 个多边形');// 飞到这个多边形的位置// map.fitBounds(polygon.getBounds());
### PART 5: 信息窗口(入口、Popup、定制) Demo 5
库引用 如上 Demo 1
// 画一个circleconst circle = L.circle([36.92, 121.31], { color: 'green', //描边色 fillColor: '#f03', //填充色 fillOpacity: 0.5, //透明度 radius: 10000 //半径,单位米}).addTo(map);// 绑定一个弹窗circle.bindPopup('我是个圆');
// 定位一个makerconst marker = L.marker([36.52, 120.31]).addTo(map);//maker上自定义一个popupconst html = '<p>Hello world!<br />This is a nice popup.</p>';const popup = marker.bindPopup(html, { maxHeight: 250, maxWidth: 490, className: 'content', offset: [0, 0] }).on('popupopen', function (params) { console.log(params)});
const mypop = L.popup();map.on('click', function (e) { mypop.setLatLng(e.latlng) .setContent('你临幸了这个点:<br>' + e.latlng.toString()) .openOn(map);});
### PART 6: geojson 数据绘制边界(坐标转换、渲染) Demo 6
// 请求geojson并处理数据const population = () => { $.get("./js/geojson.json", function (response) { const poplData = response.data const PolygonsCenter = response.geopoint drawPolygons(poplData, PolygonsCenter) });}
模拟后台返回的数据geojson
let oPolygon_VilPop = [];const legend = L.control({ position: 'bottomright' }); const drawPolygons = (poplData, PolygonsCenter) => { for (const i in poplData) { poplData[i].geoJson = JSON.parse(poplData[i].geoJson) oPolygon_VilPop[i] = L.geoJSON(poplData[i].geoJson, { style: function () { return { color: 'white', fillColor: getBgColor(poplData[i].population), //获取边界的填充色 fillOpacity: 0.6, weight: 3, dashArray: '10' }; } }).bindTooltip(poplData[i].villageName + '<br><br>人口' + poplData[i].population + '人', { direction: 'top' }).on({ mouseover: highlight, //鼠标移动上去高亮 mouseout: resetHighlight, //鼠标移出恢复原样式 click: zoomTo //点击最大化 }).addTo(oMap); } // 添加图例 legend.onAdd = legendHtml; legend.addTo(oMap); // 定位到该界限的中心位置 oMap.flyToBounds(PolygonsCenter);} // 添加图例legend.onAdd = legendHtml;legend.addTo(oMap);// 定位到该界限的中心位置oMap.flyToBounds(PolygonsCenter);}
const getBgColor = (d) => { return d > 400 ? '#800026' : d > 300 ? '#BD0026' : d > 200 ? '#FC4E2A' : d > 100 ? '#FD8D3C' : d > 50 ? '#FED976' : '#FFEDA0';}const legendHtml = (map) => { var div = L.DomUtil.create('div', 'legend locateVP_legend'), grades = [0, 50, 100, 200, 400], labels = [], from, to; for (var i = 0; i < grades.length; i++) { from = grades[i]; to = grades[i + 1]; labels.push( '<i style="background:' + getBgColor(from + 1) + '"></i> ' + from + (to ? ' ∼ ' + to + '人' : '以上')); } div.innerHTML = labels.join('<br>'); return div; };
const highlight = (e) => { var layer = e.target; layer.setStyle({ weight: 6, color: '#fff', fillOpacity: 0.9, dashArray: '0' })}const resetHighlight = (e) => { var layer = e.target; layer.setStyle({ color: 'white', weight: 3, fillOpacity: 0.6, dashArray: '10' })}const zoomTo = (e) => { oMap.fitBounds(e.target.getBounds());}
Leaflet.ChineseTmsProviders Provider for Chinese Tms Service
import 'leaflet/dist/leaflet.css';
Uncaught ReferenceError: proj4 is not defined
if (!proj4) { warn('L.esri.TiledMapLayer is using a non-mercator spatial reference. Support may be available through Proj4Leaflet http://esri.github.io/esri-leaflet/examples/non-mercator-projection.html');}
问题就出在这里,esri-leaflet里的一个插件proj4leaflet依赖proj4,所以需要手动引入proj4这个包。npm i proj4
然后再引入进来好了 `
import * as proj4 from 'proj4';window['proj4'] = proj4;`
<script src="https://cdnjs.cloudflare.com/ajax/libs/proj4js/2.4.4/proj4-src.js"></script>
持续更新中 原文地址: https://juejin.im/post/5a6586...
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