ArcGIS API For Javascript调用GP服务
1.引言
ArcGIS API中关于GP服务的调用是比较容易出错的，出错的大部分原因便是Web API调用GP服务的时候参数不对应导致的，在以前我们发布了一个自己定义的缓冲区分析的GP服务，如果不会自己发布GP服务，请先看：自己发布GP服务
2.ArcGIS API调用GP服务
首先我们先看一下服务的定义：
仔细观察了服务的定义，然后接下来我们将在Web中调用我们的GP服务
2.1代码实现
- 在页面加入地图（略）
- 在页面添加两个按钮（第一个按钮用于画点，第二个按钮用于缓冲区分析）
<input id="Btn" type="button" value="画点" />
<input id="buffer" type="button" value="缓冲区分析" />
- 定义一个点几何对象（与服务定义的类型对应）
//定义点几何对象
var pointSet = new FeatureSet();- 定义点符号对象
var psymbol = new SimpleMarkerSymbol(SimpleMarkerSymbol.STYLE_CROSS, 12,
new SimpleLineSymbol(SimpleLineSymbol.STYLE_SOLID,
new dojo.Color([255, 0, 0]), 2),
new dojo.Color([0, 255, 0, 0.25]));- 给画点按钮绑定点击事件
on(dom.byId("Btn"),"click",function(e){
//定义绘图对象
var toolBar= new Draw(MyMap, { showTooltips: true });
//激活绘图对象
toolBar.activate(Draw.POINT);
on(toolBar, "draw-complete", function(result){
//获得绘图结束的点对象
var geometry = result.geometry;
//根据点对象生成相应的图形
var graphic = new Graphic(geometry, psymbol);
//将点对象存储在点几何中
pointSet.features.push(graphic);
//将图形存放在地图中，然后得以显示
MyMap.graphics.add(graphic);
});
});- 给缓冲区分析按钮添加绑定事件
on(dom.byId("buffer"),"click",function(e){
//定义GP服务对象
var buffer = new Geoprocessor("http://localhost:6080/arcgis/rest/services/Test/MyBuffer/GPServer/Mybuffer");
//构建GP服务参数
var gpParams={};
//GP服务的Input参数
gpParams.Input=pointSet;
//GP服务的dis参数
var dis=new LinearUnit({
"distance": 100,
"units": "esriMeters"
});
gpParams.dis=dis;
//执行GP服务
buffer.execute(gpParams, showResult);
})- 处理GP服务返回的结果
function showResult(results, messages){
var features = results[0].value.features;
for (var i = 0; i < features.length; i++) {
var graphic = features[i];
//定义线符号
var lineSymbol=new SimpleLineSymbol(SimpleLineSymbol.STYLE_DASHDOT, new dojo.Color([255, 0, 0]), 1);
//定义面符号
var PolygonSymbol = new SimpleFillSymbol(SimpleFillSymbol.STYLE_SOLID, lineSymbol, new dojo.Color([255, 255, 0, 0.25]));
//设置面符号
graphic.setSymbol(PolygonSymbol);
MyMap.graphics.add(graphic);
}
}2.2 运行代码发现错误
当我们运行程序发现提示错误：
此时我们观察前台传给后台的参数：
Input:{
"geometryType":"esriGeometryPoint",
"features":[{"geometry":{"x":21264961.8441914,"y":3997922.462940743,"spatialReference":{"wkid":2334,"latestWkid":2334}}}],
"sr":{"wkid":2334,"latestWkid":2334}
}
dis: {"distance":100,"units":"esriMeters"}传给后台的参数和GP服务的参数对比，发现Input参数，缺少fields字段：
2.3修改错误
我们给运行GP服务之前给Input参数添加上Fields字段:
on(dom.byId("buffer"),"click",function(e){
//定义GP服务对象
var buffer = new Geoprocessor("http://localhost:6080/arcgis/rest/services/Test/MyBuffer/GPServer/Mybuffer");
//构建GP服务参数
var gpParams={};
//添加fields字段，为了和后台服务字段匹配
pointSet.fields=[];
//GP服务的Input参数
gpParams.Input=pointSet;
//GP服务的dis参数
var dis=new LinearUnit({
"distance": 100,
"units": "esriMeters"
});
gpParams.dis=dis;
//执行GP服务
buffer.execute(gpParams, showResult);
});2.4 全部代码
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
<title>GP</title>
<link rel="stylesheet" type="text/css" href="http://localhost/arcgis_js_api/library/3.17/3.17/dijit/themes/tundra/tundra.css"/>
<link rel="stylesheet" type="text/css" href="http://localhost/arcgis_js_api/library/3.17/3.17/esri/css/esri.css" />
<script type="text/Javascript" src="http://localhost/arcgis_js_api/library/3.17/3.17/init.js"></script>
<style type="text/css">
.MapClass{
width:100%;
height:600px;
border:1px solid #000;
}
</style>
<script type="text/javascript" charset="utf-8">
require(["esri/map",
"esri/layers/ArcGISDynamicMapServiceLayer",
"dojo/dom",
"esri/tasks/Geoprocessor",
"esri/tasks/FeatureSet",
"esri/symbols/SimpleMarkerSymbol",
"esri/symbols/SimpleLineSymbol",
"esri/toolbars/draw",
"esri/symbols/SimpleFillSymbol",
"dojo/on","esri/graphic",
"esri/tasks/LinearUnit",
"dojo/domReady!"],
function (Map,
ArcGISDynamicMapServiceLayer,
dom,
Geoprocessor,
FeatureSet,
SimpleMarkerSymbol,
SimpleLineSymbol,
Draw,
SimpleFillSymbol,on,Graphic,LinearUnit) {
var MyMap = new Map("MyMapDiv");
var layer = new ArcGISDynamicMapServiceLayer
("http://localhost:6080/arcgis/rest/services/Test/ft/MapServer");
MyMap.addLayer(layer);
//定义点几何对象
var pointSet = new FeatureSet();
var psymbol = new SimpleMarkerSymbol(SimpleMarkerSymbol.STYLE_CROSS, 12,
new SimpleLineSymbol(SimpleLineSymbol.STYLE_SOLID,
new dojo.Color([255, 0, 0]), 2),
new dojo.Color([0, 255, 0, 0.25]));
on(dom.byId("Btn"),"click",function(e){
//定义绘图对象
var toolBar= new Draw(MyMap, { showTooltips: true });
//激活绘图对象
toolBar.activate(Draw.POINT);
on(toolBar, "draw-complete", function(result){
//获得绘图结束的点对象
var geometry = result.geometry;
//根据点对象生成相应的图形
var graphic = new Graphic(geometry,psymbol);
//将点对象存储在点几何中
pointSet.features.push(graphic);
//将图形存放在地图中，然后得以显示
MyMap.graphics.add(graphic);
});
});
on(dom.byId("buffer"),"click",function(e){
//定义GP服务对象
var buffer = new Geoprocessor("http://localhost:6080/arcgis/rest/services/Test/MyBuffer/GPServer/Mybuffer");
//构建GP服务参数
var gpParams={};
//添加fields字段，为了和后台服务字段匹配
pointSet.fields=[];
//GP服务的Input参数
gpParams.Input=pointSet;
//GP服务的dis参数
var dis=new LinearUnit({
"distance": 100,
"units": "esriMeters"
});
gpParams.dis=dis;
//执行GP服务
buffer.execute(gpParams, showResult);
});
function showResult(results, messages)
{
var features = results[0].value.features;
for (var i = 0; i < features.length; i++) {
var graphic = features[i];
//定义线符号
var lineSymbol=new SimpleLineSymbol(SimpleLineSymbol.STYLE_DASHDOT, new dojo.Color([255, 0, 0]), 1);
//定义面符号
var PolygonSymbol = new SimpleFillSymbol(SimpleFillSymbol.STYLE_SOLID, lineSymbol, new dojo.Color([255, 255, 0, 0.25]));
//设置面符号
graphic.setSymbol(PolygonSymbol);
MyMap.graphics.add(graphic);
}
}
});
</script>
</head>
<body>
<div id="MyMapDiv" class="MapClass"></div>
<input id="Btn" type="button" value="画点" />
<input id="buffer" type="button" value="缓冲区分析" />
</body>
</html>运行之后的结果为：
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