ArcGiS Api For JavaScript之绘制点Graphic

已被阅读 1660 次 | 文章分类:ArcGIS API For Javascript | 2018-03-07 00:46

一副地图有很多图层组成，图层包括点图层，线图层，面图层，在WebGIS开发中生成点线面是经常要用到的基本功能，该文章以绘制点Graphic为例介绍绘制的基本原理;

一:绘制原理

利用ArcGIS API绘制的Graphic有四个基本属性:几何、符号、属性、信息模板; 几何:点要素的基本空间信息，如经纬度坐标; 符号:点要素显示的样式; 属性:点拥有的属性信息，如一个电线杆的长度，直径等信息; 信息模板:通过点击点要素可以弹窗展示属性信息;

二:代码实例

                                        
<!DOCTYPE html>
<html>
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
    <meta name="viewport" content="initial-scale=1, maximum-scale=1, user-scalable=no">
    <title>Graphic_Point</title>
    <link rel="stylesheet" href="https://js.arcgis.com/3.23/esri/css/esri.css">
    <style>
        html, body, #map {
            height: 100%;
            width: 100%;
            margin: 0;
            padding: 0;
        }
    </style>
    <script src="https://js.arcgis.com/3.23/"></script>
    <script>
      var map;
      require([
        "esri/map",
        "esri/SpatialReference",    
        "esri/symbols/TextSymbol",
        "esri/Color",
        "esri/geometry/Point",
        "esri/symbols/SimpleMarkerSymbol",
        "esri/InfoTemplate",
        "esri/graphic",
        "esri/layers/GraphicsLayer",
        "dojo/domReady!"
      ], function (
          Map,
          SpatialReference,
          TextSymbol,
          Color,
          Point,
          SimpleMarkerSymbol,
          InfoTemplate,
          Graphic,
          GraphicsLayer)
      {
        var sr= new SpatialReference({ "wkid": 4326 });
        // 定义map实例对象
        map = new Map("map", {
            center:[116.423816,39.909401],
            basemap:"topo"
        });
       
        //定义点Graphic对象
        var pt = new Point(116.423816, 39.909401, sr)
        var sms = new SimpleMarkerSymbol().setStyle(SimpleMarkerSymbol.STYLE_DIAMOND).setColor(new Color([255, 0, 0, 0.5]));
        var attr = { "Xcoord": 116.423816, "Ycoord": 39.909401, "Name": "BeiJing" };
        var infoTemplate = new InfoTemplate("Basic Info", "Latitude: ${Ycoord} <br/> Longitude: ${Xcoord} <br/>Name:${Name}");
        var graphic = new Graphic(pt, sms, attr, infoTemplate);


        //定义点的标注对象
        var Labelsymbol = new TextSymbol("北京").setColor(new Color("#ff0d08"));
        Labelsymbol.font.setSize("11pt");
        Labelsymbol.font.setFamily("KaiTi");
        Labelsymbol.setOffset(30, 0)
        var ptlabelgraphic = new Graphic(pt, Labelsymbol);


        //定义存放Graphic的图层对象
        var ptgraphLayer = new GraphicsLayer();
        var ptlabelLayer = new GraphicsLayer();
        //添加Graphic对象和标注对象到对应的GraphicsLayer
        ptgraphLayer.add(graphic);
        ptlabelLayer.add(ptlabelgraphic);
        //添加图层对象到地图中
        map.addLayers([ptgraphLayer, ptlabelLayer]);
      });
    </script>
</head>
<body>
    <div id="map"></div>
</body>
</html>

三:运行效果

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