目的：
1.ArcGIS API for Flex用GeometryService實現點、線、面的buffer分析。
準備工作：
1.在ArcGIS.Server.9.3發布一個叫USA的Map Service。
2.在ArcGIS.Server.9.3發布一個叫Geometry的Geometry Service，默認設置就可以了。
完成后的效果圖：

開始：
0.首先介紹一下Geometry Service，Geometry Service是給程序提供幾何計算如?buffering, simplifying, calculating areas 、lengths,? projecting等功能，Geometry Service可以用來代替ArcObjects 或geoprocessing service等做的這些幾何計算，它是ArcGIS Server 9.3提供的新功能，本篇就是用它來實現buffer的分析。
1.啟動Flex Builder3新建工程以及引入1.0正式版的ArcGIS API for Flex library的開發包。
2.新建bufferTest.mxml頁面，添加Map、ArcGISDynamicMapServiceLayer、GraphicsLayer等。具體代碼如下： 1<mx:Canvas?width="490"?height="401"?borderStyle="solid"?borderThickness="3"?verticalCenter="16"?left="10">
2????<esri:Map?id="myMap"?crosshairVisible="true">
3????????<esri:ArcGISDynamicMapServiceLayer?url="http://jh-53a435fbc0e8/ArcGIS/rest/services/USA/MapServer"?/>
4????????<esri:GraphicsLayer?id="myGraphicsLayer"??/>
5????</esri:Map>
6????</mx:Canvas> 3. 然后在Map控件的右邊在添加一個Grid用來顯示buffer分析后的數據，代碼如下： 1<mx:DataGrid?id="datalist"?height="398"?verticalCenter="14"?borderStyle="solid"?borderThickness="3"?left="508">
2????</mx:DataGrid> 4.這里既然是用Geometry Service實現buffer的當然還需要添加esri:GeometryService控件，它的url屬性就是上面發布的叫Geometry的Geometry Service的地址，代碼如下： 1<esri:GeometryService?id="myGeometryService"?url="http://jh-53a435fbc0e8/ArcGIS/rest/services/Geometry/GeometryServer"/> 5.這里采用在地圖上畫點、線、面然后根據畫的幾何圖進行buffer,所以還需要ToggleButtonBar按鈕組控件、Draw控件以及圖形顯示樣式的定義，具體代碼如下： ?1<esri:SimpleFillSymbol?id="sfs"?color="0xFF0000"?alpha="0.6">
?2????</esri:SimpleFillSymbol>
?3????<esri:Draw?id="drawToolbar"?map="{myMap}"?graphicsLayer="{myGraphicsLayer}"?drawEnd="drawEndHandler(event)"?/>
?4????<mx:ToggleButtonBar?verticalCenter="-203"??itemClick="itemClickHandler(event)"?toggleOnClick="true"?left="11">
?5????????<mx:dataProvider>
?6????????<mx:Array>
?7????????<mx:Object?icon="{point}"?/>
?8????????<mx:Object?icon="{polyline}"?/>
?9????????<mx:Object?icon="{polygon}"?/>
10????????</mx:Array>
11????????</mx:dataProvider>
12????</mx:ToggleButtonBar> 6.point、polyline、polygon的icon定義如下： ?1<mx:Script>
?2????????<![CDATA[
?3???????????????????
?4????????[Bindable]?
?5????????????[Embed(source="assets/point.gif")]
?6????????????public?var?point:Class;?
?7
?8????????????[Bindable]?
?9????????????[Embed(source="assets/polyline.gif")]
10????????????public?var?polyline:Class;?
11
12????????????[Bindable]?
13????????????[Embed(source="assets/polygon.gif")]
14????????????public?var?polygon:Class;?
15????????????????????
16????????????]]>
17????</mx:Script> 7.進行buffer后得到的圖形然后用來查詢相關結果了所以還需要添加IdentifyTask控件，代碼如下： 1<esri:IdentifyTask?id="identifyTask"?identifyComplete="identifyCompleteHandler(event)"?url="http://jh-53a435fbc0e8/ArcGIS/rest/services/USA/MapServer"/> 8.接下來開始編寫功能代碼，過程首先是用Draw工具在GraphicsLayer上畫幾何圖形，然后用GeometryService對幾何圖形進行buffer，然后用分析得到的結果圖形進行IdentifyTask出結果顯示在DataGrid中。
9.按照上面的過程首先添加ToggleButtonBar的itemClick事件方法itemClickHandler(event)，代碼如下： ?1private?function?itemClickHandler(event:ItemClickEvent):void
?2????????????{
?3????????????????switch(event.index)
?4????????????????{
?5????????????????????case?0:
?6????????????????????{
?7????????????????????????drawToolbar.activate(Draw.MAPPOINT);
?8????????????????????????break;
?9????????????????????}
10????????????????????case?1:
11????????????????????{
12????????????????????????drawToolbar.activate(Draw.POLYLINE);
13????????????????????????break;
14????????????????????}
15????????????????????case?2:
16????????????????????{
17????????????????????????drawToolbar.activate(Draw.POLYGON);
18????????????????????????break;
19????????????????????}
20????????????????}
21????????????} 10.接著是Draw控件的drawEnd時間方法drawEndHandler(event)，代碼如下： ?1private?function?drawEndHandler(event:DrawEvent):void
?2????????????{
?3????????????????var?myGraphic:Graphic=event.graphic;
?4????????????????//設置buffer參數
?5????????????????var?bufferParameters?:?BufferParameters?=?new?BufferParameters();
?6????????????????bufferParameters.features=[myGraphic];
?7????????????????//buffer距離半徑
?8????????????????bufferParameters.distances?=?[100000];
?9????????????????//buffer單位
10????????????????bufferParameters.unit?=?BufferParameters.UNIT_METER;
11????????????????//buffer空間參照系,102113為WKID是REST?API定義好的空間參照系的id
12????????????????bufferParameters.bufferSpatialReference?=?new?SpatialReference(102113);??????????????????????????
13????????????????//添加BUFFER_COMPLETE監聽
14????????????????myGeometryService.addEventListener(GeometryServiceEvent.BUFFER_COMPLETE,?bufferCompleteHandler);??
15????????????????//進行buffer分析
16????????????????myGeometryService.buffer(?bufferParameters?);
17????????????} 11.上面的代碼中用GeometryService進行buffer已經有詳細注釋了,執行buffer方法后會執行bufferCompleteHandler方法，代碼如下： ?1//buffer完成后調用方法
?2????????????private?function?bufferCompleteHandler(?event?:?GeometryServiceEvent?)?:?void
?3????????????{
?4????????????????myGraphicsLayer.clear();
?5????????????????//移除BUFFER_COMPLETE監聽
?6????????????????myGeometryService.removeEventListener(GeometryServiceEvent.BUFFER_COMPLETE,bufferCompleteHandler);
?7????????????????//獲取buffer結果Graphic
?8????????????????for?each?(var?graphic?:?Graphic?in?event.graphics?)
?9????????????????{
10????????????????????//設置顯示樣式
11????????????????????graphic.symbol?=?sfs;
12????????????????????//添加到GraphicsLayer進行顯示
13????????????????????myGraphicsLayer.add(?graphic?);
14????????????????????
15????????????????????var?identifyParams:IdentifyParameters=new?IdentifyParameters();
16????????????????????//查詢結果需要返回Geometry
17????????????????????identifyParams.returnGeometry=true;
18????????????????????//查詢冗余范圍
19????????????????????identifyParams.tolerance=1;
20????????????????????//寬
21????????????????????identifyParams.width?=?myMap.width;
22????????????????????//高
23????????????????????identifyParams.height?=?myMap.height;
24????????????????????//設置查詢的Geometry
25????????????????????identifyParams.geometry=graphic.geometry;
26????????????????????//從ComboBox獲取選擇的圖層index設置要查詢的圖層
27????????????????????//查詢圖層id為2的圖層，就是States層
28????????????????????identifyParams.layerIds=[2];
29????????????????????//查詢可見圖層
30????????????????????//identifyParams.layerOption=IdentifyParameters.LAYER_OPTION_VISIBLE;
31????????????????????identifyParams.mapExtent=myMap.extent;
32????????????????????//進行查詢
33????????????????????identifyTask.execute(identifyParams);
34????????????????}
35????????????} 12.上面的代碼中在最后執行了IdentifyTask的execute方法進行Identify查詢，查詢結束后會調用identifyCompleteHandler方法把結果顯示在DataGrid中，代碼如下： ?1//查詢完成后執行的事件
?2????????????private?function?identifyCompleteHandler(event:IdentifyEvent):void
?3????????????{
?4????????????????myNav.activate(Navigation.PAN);
?5????????????????var?datas:Array=new?Array();
?6????????????????//myGraphicsLayer.clear();
?7????????????????//遍歷查詢結果把查詢到的feature添加到GraphicsLayer進行高亮顯示
?8????????????????//同時把查詢到的元素的名稱添加到datas對象數組用來DataGrid顯示用
?9????????????????for?each?(var?result:IdentifyResult?in?event.identifyResults)
10????????????????{
11????????????????????myGraphicsLayer.add(result.feature);
12????????????????????//datas.push(result.feature.attributes);????
13????????????????????datas.push({"value":result.value});
14????????????????}
15????????????????//設置mx:DataGrid的數據源
16????????????????datalist.dataProvider=datas;
17????????????} 13.這樣就完成了buffer的功能，運行測試效果。

轉載于:https://www.cnblogs.com/hll2008/archive/2008/10/28/1321595.html

總結

以上是生活随笔為你收集整理的ArcGIS.Server.9.3和ArcGIS API for Flex的GeometryService和buffer分析（十）的全部內容，希望文章能夠幫你解決所遇到的問題。

如果覺得生活随笔網站內容還不錯，歡迎將生活随笔推薦給好友。