基础功能---几何服务_缓冲区

1.效果图

2.启用几何服务

和发布的地图一样，通过REST URL调用

3.引入模块

"esri/toolbars/draw",
"esri/graphic",
"esri/tasks/GeometryService",
"esri/tasks/BufferParameters",
"dojo/colors",

4.步骤

创建几何服务对象

//这里是几何服务的REST URL
var geometryServices = new GeometryService("http://localhost:6080/arcgis/rest/services/Utilities/Geometry/GeometryServer");

创建缓存参数对象
```
var params = new BufferParameters();
```

使用toolbar上的绘图工具

var toolBar = new Draw(map);

创建点，线，面

var pointSymbol = new SimpleMarkerSymbol();
lineSymbol = new SimpleLineSymbol(SimpleLineSymbol.STYLE_DASH, new Color([255, 0, 0]), 2);
polygonSymbol = new SimpleFillSymbol(SimpleFillSymbol.STYLE_SOLID, lineSymbol, new Color([255, 255, 0, 0.25]));

给画点按钮绑定事件

on(dom.byId("point"), "click", function () {
    //激活画点工具
    toolBar.activate(Draw.POINT, {
    showTooltips: true
    })
})

绘图结束绑定事件

on(toolBar, "draw-end", function (result) {
    //获得点形状
    var geometry = result.geometry;
    //创建Graphic
    var graphicpoint = new Graphic(geometry, pointSymbol);
    map.graphics.add(graphicpoint);
    //关闭绘图工具
    toolBar.deactivate();

    // *** 构建缓冲区分析的形状属性
    //注意这里可以放一个数组，此处为了方便我们只对一个形状进行缓冲区分析
    params.geometries = [geometry];
})

给缓冲区分析按钮绑定事件

on(dom.byId("Btn"), "click", function () {
    var mi = $("#te").val();
    //缓冲距离
    params.distances = [mi];
    //空间参考，缓冲区样式，透明度等
    params.bufferSpatialReference = map.spatialReference;
    params.outSpatialReference = map.spatialReference;
    //执行分析处理结果
    geometryServices.buffer(params, function (result) {
        //处理缓冲区分析得到的结果
        for (var idx in result) {
            //创建Graphic
            var graphic = new Graphic(result[idx], polygonSymbol)
            //结果放在map中
            map.graphics.add(graphic)
        }
    });
})

5. 贴代码

<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">

<head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    <title>缓冲区分析</title>
    <link rel="stylesheet" href="https://js.arcgis.com/3.28/esri/css/esri.css" />
    <script src="https://js.arcgis.com/3.28/"></script>
    <script  src="https://code.jquery.com/jquery-1.12.4.js"></script>
    <style type="text/css">
        .MapClass {
            width: 100%;
            height: 900px;
        }
    </style>
    <script type="text/javascript">


        require(["esri/map",
            "dojo/dom", "dojo/on",
            "esri/layers/ArcGISDynamicMapServiceLayer",
            "esri/symbols/SimpleMarkerSymbol",
            "esri/symbols/SimpleLineSymbol",
            "esri/symbols/SimpleFillSymbol",
            "esri/toolbars/draw",
            "esri/graphic",
            "esri/tasks/GeometryService",
            "esri/tasks/BufferParameters",
            "dojo/colors",
            "dojo/domReady!"],
            function (Map, dom, on,
                ArcGISDynamicMapServiceLayer,
                SimpleMarkerSymbol,
                SimpleLineSymbol,
                SimpleFillSymbol,
                Draw,
                Graphic,
                GeometryService,
                BufferParameters, Color) {
                var map = new esri.Map("mapDiv");
                var layer = new esri.layers.ArcGISDynamicMapServiceLayer
                    ("http://localhost:6080/arcgis/rest/services/ecology/beijing_2012_3/MapServer");
                map.addLayer(layer);


                //创建几何服务对象
                var geometryServices = new GeometryService("http://localhost:6080/arcgis/rest/services/Utilities/Geometry/GeometryServer");
                //创建缓存参数对象
                var params = new BufferParameters();

                //使用toolbar上的绘图工具
                var toolBar = new Draw(map);
                //创建点符号
                var pointSymbol = new SimpleMarkerSymbol();
                pointSymbol.style = SimpleMarkerSymbol.STYLE_CIRCLE;
                pointSymbol.setSize(10);
                pointSymbol.setColor(new Color("#FFFFCC"));
                //线符号
                lineSymbol = new SimpleLineSymbol(SimpleLineSymbol.STYLE_DASH, new Color([255, 0, 0]), 2);
                //面符号
                polygonSymbol = new SimpleFillSymbol(SimpleFillSymbol.STYLE_SOLID, lineSymbol, new Color([255, 255, 0, 0.25]));
                //给画点按钮绑定事件
                on(dom.byId("point"), "click", function () {
                    //激活画点工具
                    toolBar.activate(Draw.POINT, {
                        showTooltips: true
                    })

                })
                //绘图结束绑定事件
                on(toolBar, "draw-end", function (result) {
                    //获得点形状
                    var geometry = result.geometry;
                    //创建Graphic
                    var graphicpoint = new Graphic(geometry, pointSymbol);
                    map.graphics.add(graphicpoint);
                    //关闭绘图工具
                    toolBar.deactivate();
                    //很重要！！！在这里构建缓冲区分析的形状属性
                    //注意这里可以放一个数组，此处为了方便我们只对一个形状进行缓冲区分析
                    params.geometries = [geometry];


                })
                //给缓冲区分析按钮绑定事件
                on(dom.byId("Btn"), "click", function () {
                    // var mi = document.getElementById("te").value;
                    var mi = $("#te").val();
                    //缓冲距离
                    params.distances = [mi];
                    //空间参考
                    params.bufferSpatialReference = map.spatialReference;
                    params.outSpatialReference = map.spatialReference;
                    //执行分析处理结果
                    geometryServices.buffer(params, function (result) {
                        //处理缓冲区分析得到的结果
                        for (var idx in result) {
                            //创建Graphic
                            var graphic = new Graphic(result[idx], polygonSymbol)
                            //将每一个结果都放在map中
                            map.graphics.add(graphic)
                        }
                    });


                })

            });
    </script>
</head>

<body>
    <div id="mapDiv" class="MapClass"></div>
    <input id="point" type="button" value="点" />
    <input id="te" type="text" value="缓冲距离">
    <input id="Btn" type="button" value="缓冲区分析" />
</body>

</html>

6. 拓展

对连续点进行缓冲区操作，怎么消除上一个操作的缓冲区？
怎么连续选点，批量建立缓冲区？