1.引言
由于Arcgis for javascript API不可以绘制Geojson,并且提供的Popup一般只可以弹出一个,在很多专题图制作中,会遇到不少的麻烦。因此本文结合了两个现有的Arcgis for javascript API扩充库,对其进行改造达到绘制Geojson并同时弹出多个Popup的目的。
目前已有的两个扩充库github地址(可供单独使用):
1.绘制Geojson的扩充库:https://github.com/Esri/geojson-layer-js
2.多个Popup显示的扩充库:https://github.com/nickcam/PopupExtended
本文实现的效果图:
图1 上海5个地点的部分预报属性 图2 上海某三条航线的部分预报属性
2. 各类依赖库引入及前端HTML
首先需要先载入需要用的常用js、Arcgis及两个扩充库的js及部分css(下载地址见其github):
<!DOCTYPE html> <html> <head><title>Add GeoJSON and Display Multiple Popup</title><meta http-equiv="Content-Type" content="text/html; charset=utf-8"><meta http-equiv="X-UA-Compatible" content="IE=7,IE=9"><meta name="viewport" content="initial-scale=1, maximum-scale=1,user-scalable=no"><!-- ArcGIS API for JavaScript CSS--><link rel="stylesheet" href="http://js.arcgis.com/3.13/esri/css/esri.css"><link rel="stylesheet" href="http://js.arcgis.com/3.13/dijit/themes/claro/claro.css"><!-- Web Framework CSS - Bootstrap (getbootstrap.com) and Bootstrap-map-js (github.com/esri/bootstrap-map-js) --><link rel="stylesheet" href="//netdna.bootstrapcdn.com/bootstrap/3.1.1/css/bootstrap.min.css" rel="stylesheet"><link rel="stylesheet" href="./css/bootstrap.min.css"><!-- PopExtendCss --><link href="./vendor/ncam/PopupExtended.css" rel="stylesheet" /><!-- PopupExtended references --><script>var dojoConfig = {parseOnLoad: false,async: true,tlmSiblingOfDojo: false,packages: [{name: "ncam",location: location.pathname.replace(/\/[^/]+$/, '') + "ncam" }]};</script><!-- ArcGIS API for JavaScript library references --><script src="//js.arcgis.com/3.10"></script><!-- Terraformer reference --><script src="./vendor/terraformer/terraformer.min.js"></script> <script src="./vendor/terraformer-arcgis-parser/terraformer-arcgis-parser.min.js"></script><!-- other reference --><script src="./vendor/jquery.js"></script> </head> <body></body> </html>
加入底图所需要的div与图层切换的Button:
<body><div id="mapDiv"></div><button type="line" id="shanghaiPoint" class="btn btn-default buttonRight" style="top:20px;right:20px">上海区各点</button><button type="point" id="threeLine" class="btn btn-default buttonRight" style="top:70px;right:20px">三条航线</button> </body>
3.置入Popupextended并扩充geojsonlayer.js
然后从geojsonlayer.js源码入手,开始将PopupExtended扩展其中,让我们新构建的geojsonlayer直接可拥有多个Popup。在geojsonlayer.js的constructor中很容易可以找出infotemplate的set方法:
// Default popupif (options.infoTemplate !== false) {this.setInfoTemplate(options.infoTemplate || new InfoTemplate("GeoJSON Data", "${*}"));}
很明显,geojsonlayer初始化时通过options传入参数进行判断并构造,所以实现本文目的的大致思路是将这里的setInfoTemplate替换成可以扩展的PopupExtended:
if (options.infoTemplate !== false) {//① create a PopupTemplatevar template = new PopupTemplate({title: "{name}",fieldInfos: [{ fieldName: "Id", label: "Id", visible: true },{ fieldName: "publishdate", label: "观测日期", visible: true },{ fieldName: "waveheight", label: "浪高", visible: true },{ fieldName: "wavedirection", label: "浪向", visible: true },{ fieldName: "windspeed", label: "风速", visible: true },{ fieldName: "winddirection", label: "风向", visible: true },{ fieldName: "comfort", label: "等级", visible: true }],extended: { actions: [{ text: " IconText", className: "iconText", title: "Custom action with an icon and Text", click: function (feature) { alert("Icon Text clicked on " + "id: " + feature.attributes.id + " " + feature.attributes.name); } },{ text: "", className: "iconOnly", title: "Custom action only using an icon", click: function (feature) { alert("Icon action clicked on " + "id: " + feature.attributes.id + " " + feature.attributes.name); } } ],//uses a pretty bad custom theme defined in PopupExtended.css.scaleSelected: 1.6}});//② create a extend for basemapvar extendedPopup = new PopupExtended({extended: {themeClass: "light",draggable: true,defaultWidth: 250,actions: [{text: "其他", className: "defaultAction", title: "Default action added in extendedPopup properties.",click: function (feature) { alert("clicked feature - " + feature.attributes); }}],hideOnOffClick: false,multiple: true,},highlight: false,//titleInBody: false,}, dojo.create("div"));//③set the map to use the exteneded popup extendedPopup.setMap(options.baseMap);options.baseMap.infoWindow = extendedPopup;this.setInfoTemplate(options.infoTemplate || template);}
由上段代码可见,引入Popup给GeoJSON共分为三步:①实例化一个你需要的PopupTemplate(这里起名为template),可指定你需要展示的主题、数据项及扩展的一些交互action;②实例化一个PopupExtended并设置一些默认的Popup属性;③将实例化的PopupExtended——extendedPopup的Map设置为baseMap,并将baseMap的infowindow设置为extendedPopup,最后将geojsonlayer的infoTemplate设置为新构建的template。这样便可以实现对置入底图的geojsonlayer进行多个infoTemplate展示需求了。源代码见github:展示效果如图3:
图3 对geojsonlayer扩充Popupextended后的显示效果
如若只需增加多个Popup至geojsonlayer的话,以上部分足以实现了。
4.增加新的Attributes及调整Popup的样式
由于设计上的需求,笔者需要从其他地址获取观测点的部分观测值,并且笔者的老师觉得应该加一些icon给属性,美化展示效果,所以需要重新构造两部分:①获取并为graphics增加新的attributes;②重构geojsonlayer的infoTemplate的content。
4.1 获取并为graphics增加新的attributes:
通过在button上利用fetch及Promise.all来同时获取6个点或3条航线的数据,并传入至初始化geojsonlayer的函数内;
$("#shanghaiPoint").click(function(){// if first init geojsonlayerif(firstPointInit){var requestBZ = 'http://wx.dhybzx.org:18080/forecast/shanghai_sea_env/80';var requestWGQ = 'http://wx.dhybzx.org:18080/forecast/shanghai_sea_env/81';var requestHS = 'http://wx.dhybzx.org:18080/forecast/shanghai_sea_env/82';var requestLCG = 'http://wx.dhybzx.org:18080/forecast/shanghai_sea_env/83';var requestJHG = 'http://wx.dhybzx.org:18080/forecast/shanghai_sea_env/84';var requestJSW = 'http://wx.dhybzx.org:18080/forecast/shanghai_sea_env/85';var urls = [requestBZ, requestWGQ,requestHS,requestLCG,requestJHG,requestJSW]Promise.all(urls.map(url =>fetch(url).then(resp => resp.json()))).then(results => {var tempJson = {"堡镇":results[0][0],"外高桥":results[1][0],"横沙":results[2][0],"芦潮港":results[3][0],"金汇港":results[4][0],"金山卫":results[5][0]}addGeoJsonToMap("./data/six_point.json",tempJson)});}else{//geojsonlayer has been initialaddGeoJsonToMap("./data/six_point.json")}})
这里的Promise.all采用了ES2015的箭头函数,兼容性问题需要自己考虑,也可以手动改成ES5支持的。将额外的attributes组装成tempJson后传入至初始化方法addGeoJsonToMap内。
4.2 重构geojsonlayer的infoTemplate的content:
在geojsonlayer.js内继续做一部分修改,注释掉实例化template中的fieldInfos属性及值,并且为geojsonlayer的infoTemplate设置新的content,代码如下:
var template = new PopupTemplate({title: "{name}",// fieldInfos: [// { fieldName: "Id", label: "Id", visible: true },// { fieldName: "publishdate", label: "观测日期", visible: true },// { fieldName: "waveheight", label: "浪高", visible: true },// { fieldName: "wavedirection", label: "浪向", visible: true },// { fieldName: "windspeed", label: "风速", visible: true },// { fieldName: "winddirection", label: "风向", visible: true },// { fieldName: "comfort", label: "等级", visible: true }// ], extended: { actions: [{ text: " IconText", className: "iconText", title: "Custom action with an icon and Text", click: function (feature) { alert("Icon Text clicked on " + "id: " + feature.attributes.id + " " + feature.attributes.name); } },{ text: "", className: "iconOnly", title: "Custom action only using an icon", click: function (feature) { alert("Icon action clicked on " + "id: " + feature.attributes.id + " " + feature.attributes.name); } } ],//uses a pretty bad custom theme defined in PopupExtended.css.scaleSelected: 1.6}});//create a extend for basemapvar extendedPopup = new PopupExtended({extended: {themeClass: "light",draggable: true,defaultWidth: 250,actions: [{text: "其他", className: "defaultAction", title: "Default action added in extendedPopup properties.",click: function (feature) { alert("clicked feature - " + feature.attributes); }}],hideOnOffClick: false,multiple: true,},highlight: false,//titleInBody: false,}, dojo.create("div"));//set the map to use the exteneded popup extendedPopup.setMap(options.baseMap);options.baseMap.infoWindow = extendedPopup;this.setInfoTemplate(options.infoTemplate || template);this.infoTemplate.setContent("<b class='popupTitle'>${name}</b>" +"<div class='hzLine'></div>"+"<div class='popupContent'>"+"<i class='glyphicon glyphicon-calendar'></i><b>日期: </b> ${publishdate}<br/>"+"<i class='glyphicon glyphicon-resize-vertical'></i><b>浪高: </b> ${waveheight}<br/>" +"<i class='glyphicon glyphicon-random'></i><b>浪向: </b> ${wavedirection}<br/>"+"<i class='glyphicon glyphicon-share'></i><b>风速: </b> ${windspeed}<br/>" +"<i class='glyphicon glyphicon-transfer'></i><b>风向: </b> ${winddirection}<br/>"+"<i class='glyphicon glyphicon-export'></i><b>等级: </b> ${comfort}<br/>"+"</div>");
额外的属性和新的infoTemplate样式构造完成,但存在一个问题,即额外的attributes必须要在geojsonlayer绘制好后再进行设置并展示,arcgis提供了layer的layer-add及layer-add-result事件,但是无法监控到graphics是否已经增入至geojsonlayer内,所以必须要再做一些改进,使额外的属性能够在graphics绘制完毕后再添加进去。具体方法分为两步:1)初始化geojsonlayer时,将showAllPopup方法传入其构造函数内;2)在grahics添加至layer后,调用showAllPopup方法,显示所有的Popup。前端代码如下:
//add GeoJSON to baseMap , constuct show&hide popup method and add other attribute to graphicsfunction addGeoJsonToMap(url,otherJson){require(["esri/map","./src/geojsonlayer.js","esri/geometry/Point", "esri/SpatialReference","dojo/on","dojo/dom","dojo/domReady!"],function (Map, GeoJsonLayer, Point, SpatialReference,on, dom) {var hasThisLayer=false;otherJson=otherJson?otherJson:"";hideAllPopup()//judge layer has been initmap.getLayersVisibleAtScale().forEach(function(item){if(item._url==url&&item.dataType=="geojson"){console.log(item)item.show();console.log("dd")showAllPopup(item);hasThisLayer=true;// map.setExtent(item.extent)}else if(item._url!=url&&item.dataType=="geojson"){item.hide();}})if(!hasThisLayer){addGeoJsonLayer(url); }//show all popupsfunction showAllPopup(layer){......}//hide all popupsfunction hideAllPopup(){.......}//add other attribute to grpahics for popupfunction addAttrToGrpahics(item,type){.......}// Add the layerfunction addGeoJsonLayer(url) {// Create the layervar geoJsonLayer = new GeoJsonLayer({baseMap:map,url: url,onLayerLoaded:function(layer){showAllPopup(layer);} });// Add to mapgeoJsonLayer.dataType="geojson"; map.addLayer(geoJsonLayer);}});}
并且在geojsonlayer.js的constructor内加入:
this._onLayerLoaded = options.onLayerLoaded;
在最后的_addGraphics方法中onLoad方法后,加入:
if (this._onLayerLoaded) this._onLayerLoaded(this);
利用show/hide方法,控制popup显示及隐藏。
//open all popup layer.graphics.forEach(function(item){if(firstPointInit&&otherJson[item.attributes.name]){addAttrToGrpahics(item,layer.graphics[0].geometry.type)}var loc = map.toScreen(item.geometry);map.infoWindow.setFeatures([item]);map.infoWindow.show(loc); }) //hide all popup var tempLength = map.infoWindow.openPopups.length; for(var i=0;i<tempLength;i++){map.infoWindow.openPopups[0].hide() }
5. 结论
至此,本文已经完成了在Arcgis for javascript API中实现Geojson的绘制,并同时展示其多个Popup的需求。最终的展示效果如图1、2。源代码见笔者的github:https://github.com/EasonXu818/Add-GeoJSON-Multiple-Popups。