利用ArcGIS API For Flex+ImageServer实现Identity影像服务的值

ImageServer能够直接获得影像服务的栅格值，ImageServer支持??导出图像?，查询，识别?，?下载?操作，查看ArcGIS Server REST API的帮助得到进行Identity操作需要遵循mosicRule，mosicRule所需的参数如下：

{
  "mosaicMethod" : "<esriMosaicNone | esriMosaicCenter | esriMosaicNadir | esriMosaicViewpoint | 
                     esriMosaicAttribute | esriMosaicLockRaster | esriMosaicNorthwest | esriMosaicSeamline>","where" : "<where>","sortField" : "<sortFieldName>","sortValue" : <sortValue>,"ascending" : <true | false>,"lockRasterIds" : [<rasterId1>,<rasterId2>],"viewpoint" : <point>,"fids" : [<fid1>,<fid2>],"mosaicOperation" : "<MT_FIRST | MT_LAST | MT_MIN | MT_MAX | MT_MEAN | MT_BLEND>"
}

var imageIdentify:ImageServiceIdentifyTask=new ImageServiceIdentifyTask(imageLayer.url);
var parm:ImageServiceIdentifyParameters=new ImageServiceIdentifyParameters();
var mosaicRule:MosaicRule=new MosaicRule();
mosaicRule.ascending=false;
mosaicRule.method="esriMosaicCenter";
parm.geometry=mapPoint;
parm.mosaicRule=mosaicRule;
parm.pixelSizeX=imageLayer.pixelSizeX;
parm.pixelSizeY=imageLayer.pixelSizeY;
imageIdentify.execute(parm,new AsyncResponder(onResult,onFault));
//成功执行的操作
private function onResult(imageResult : ImageServiceIdentifyResult,token : Object = null):void
{
	var value:String=imageResult.value.toString();
}
//出现错误的操作
private function onFault(info : Object,token : Object = null):void
{
}