arcgis api for javascript 座標轉換

var lonlat={x:114.514864,y:38.04232};
var mercator={x:12747736.346966475,y:4585405.935084799};

//經緯度轉墨卡託
function lonlat2mercator(lonlat){
var mercator={x:0,y:0};
var x = lonlat.x *20037508.34/180;
var y = Math.log(Math.tan((90+lonlat.y)*Math.PI/360))/(Math.PI/180);
y = y *20037508.34/180;
mercator.x = x;
mercator.y = y;
return mercator ;
}

//墨卡託轉經緯度
function mercator2lonlat(mercator){
var lonlat={x:0,y:0};
var x = mercator.x/20037508.34*180;
var y = mercator.y/20037508.34*180;
y= 180/Math.PI*(2*Math.atan(Math.exp(y*Math.PI/180))-Math.PI/2);
lonlat.x = x;
lonlat.y = y;
return lonlat;
}

//墨卡託轉經緯度定位
var dx = sGeometry.x / 20037508.34 * 180;
var dy = sGeometry.y / 20037508.34 * 180;
var M_PI = Math.PI;
dy = 180 / M_PI * (2 * Math.atan(Math.exp(dy * M_PI / 180)) - M_PI / 2);
//地理座標x爲:122.10626710683903
//地理座標y爲:37.48735577057014
// x=dx;
// y=dy;
var cPoint=new esri.geometry.Point();
cPoint.x=dx;
cPoint.y=dy;
console.log(cPoint);
map.centerAt(cPoint);

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var geometryService = new esri.tasks.GeometryService("http://tasks.arcgisonline.com/ArcGIS/rest/services/Geometry/GeometryServer");
      
	  var incoord = 102100;  //當前座標系
           var outcoord = 4326;  //目標座標系
           var inSR = new esri.SpatialReference({wkid: incoord });
           var outSR = new esri.SpatialReference({wkid: outcoord});
	        var inputpoint = new esri.geometry.Point(evt.mapPoint.x, evt.mapPoint.y, inSR);
	        var PrjParams = new esri.tasks.ProjectParameters();
	        PrjParams.geometries = [inputpoint];
	        PrjParams.outSR = outSR;
	        
	        PrjParams.transformation = {wkid: parseInt(4326)}
            
            geometryService.project(PrjParams, function (outputpoint) {

		alert(經度："+outputpoint[0].x+",緯度："+ outputpoint[0].y);
     
	});