Geometry Service Buffer only works in WebMercator

BryanLin

So an interesting thing that I've found about the Geometry Service is that it seems to only work for geometries in WebMercator. I have a map in WGS 1984 where I tried to buffer a feature. The problem occurred when after buffering the feature, the results returned were way out of bounds of the current coordinate system. I basically dug through all the API reference with no luck until I came up with a hack:

I would use the WebMercatorUtil class and project the feature on WGS 1984 map to WebMercator, then buffer the feature in webmercator, then on the buffer complete, I would project it back to geographic with WebMercatorUtil.webMercatorToGeographic.  This seems like a bug in the ESRI Flex API and I was wondering if there will be a fix for this because anyone should be able to buffer any feature and get the result back in its original coordinate system without manually typing in code to do it.

Any thoughts?

DasaPaddock

Here's a modification of the BufferSample at:
http://help.arcgis.com/en/webapi/flex/samples/index.html?sample=BufferSample

I've fixed the myGeometryService url and changed the base layer to a 4326 service.

An example of the requests it sends is:
http://sampleserver3.arcgisonline.com/ArcGIS/rest/services/Geometry/GeometryServer/buffer?unionResults=false&f=json&bufferSR=102100&geometries=%7B%22geometryType%22%3A%22esriGeometryPoint%22%2C%22geometries%22%3A%5B%7B%22x%22%3A%2D114%2E51800371679786%2C%22y%22%3A33%2E55105676332971%7D%5D%7D&unit=9036&distances=50%2C100&inSR=4326

<?xml version="1.0" encoding="utf-8"?>
<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009"
               xmlns:s="library://ns.adobe.com/flex/spark"
               xmlns:mx="library://ns.adobe.com/flex/mx"
               xmlns:esri="http://www.esri.com/2008/ags"
               pageTitle="Buffer using the Geometry Service">
    <!--
         This sample creates buffers around the center of the map. This example just draws the buffers,
         but the buffers could also be used to perform a task such as returning a list of addresses of
         people who live within the buffered area.
    -->

    <s:controlBarLayout>
        <s:HorizontalLayout horizontalAlign="center"
                            paddingBottom="7"
                            paddingTop="7"/>
    </s:controlBarLayout>
    <s:controlBarContent>
        <s:Button click="bufferCenterOfMap()" label="Buffer Center Of Map"/>
    </s:controlBarContent>

    <fx:Declarations>
        <esri:SimpleFillSymbol id="sfs" color="0xFF0000">
            <esri:SimpleLineSymbol color="0x000000"/>
        </esri:SimpleFillSymbol>
        <esri:GeometryService id="myGeometryService" url="http://sampleserver3.arcgisonline.com/ArcGIS/rest/services/Geometry/GeometryServer"/>
    </fx:Declarations>

    <fx:Script>
        <![CDATA[
            import com.esri.ags.Graphic;
            import com.esri.ags.SpatialReference;
            import com.esri.ags.events.GeometryServiceEvent;
            import com.esri.ags.geometry.MapPoint;
            import com.esri.ags.geometry.Polygon;
            import com.esri.ags.tasks.supportClasses.BufferParameters;

            private function bufferCenterOfMap():void
            {
                var myMapCenterPoint:MapPoint = MapPoint(myMap.extent.center);

                var bufferParameters:BufferParameters = new BufferParameters();
                // Note: As of version 2.0, the GeometryService input is geometries (instead of graphics).
                bufferParameters.geometries = [ myMapCenterPoint ];
                bufferParameters.distances = [ 50, 100 ];
                // Note: As of version 2.0, the buffer constants have been moved to GeometryService.
                bufferParameters.unit = GeometryService.UNIT_KILOMETER;
                bufferParameters.bufferSpatialReference = new SpatialReference(102100);

                myGeometryService.addEventListener(GeometryServiceEvent.BUFFER_COMPLETE, bufferCompleteHandler);
                myGeometryService.buffer(bufferParameters);

                function bufferCompleteHandler(event:GeometryServiceEvent):void
                {
                    myGeometryService.removeEventListener(GeometryServiceEvent.BUFFER_COMPLETE, bufferCompleteHandler);
                    // Note: As of version 2.0, GeometryService returns geometries (instead of graphics)
                    for each (var geometry:Polygon in event.result)
                    {
                        var graphic:Graphic = new Graphic();
                        graphic.geometry = geometry;
                        graphic.symbol = sfs;
                        graphicsLayer.add(graphic);
                    }
                }
            }
        ]]>
    </fx:Script>

    <esri:Map id="myMap"
              crosshairVisible="true"
              level="2">
        <esri:ArcGISTiledMapServiceLayer url="http://server.arcgisonline.com/ArcGIS/rest/services/ESRI_StreetMap_World_2D/MapServer"/>
        <esri:GraphicsLayer id="graphicsLayer"/>
    </esri:Map>

</s:Application>