ジオメトリ サービスを使用した投影変換

require([
    "esri/tasks/GeometryService",
    "esri/tasks/ProjectParameters",
    "esri/SpatialReference"
    ],
function (
    GeometryService,ProjectParameters,SpatialReference
    ) {
 
      function addPoint(evt) {
 
        var geometryService = new GeometryService("http://tasks.arcgisonline.com/ArcGIS/rest/services/Geometry/GeometryServer");  //もしくはローカル ArcGIS Server のジオメトリ サービス
 
        var params = new ProjectParameters();
        params.geometries = [evt.mapPoint];
        params.outSR = new SpatialReference(4612);
        geometryService.project(params,function(geometries){
 
          var longitude = geometries[0].x;
          var latitude = geometries[0].y;
        });
      }
};