ESRI BufferAsync function

[VarunGoel]

Hello,

I am very new to working on ESRI Silverlight functionality and need some guidance on fixing one issue.

In the existing code (bought from 1 expereinced company on ESRI GIS), we are having a BufferAsynch functionality which is used to draw a circle around a point (Refer: http://help.arcgis.com/en/webapi/silverlight/samples/start.htm#BufferPoint).

When we are drawing the circle through BufferAsynch, the completed callback gets the response and displays a circle around the point. It works fine when we are clicking in the middle of the map to draw the circle.

But, when we click near to say, North pole, the circle becomes elliptical (horizontally very large).

On debugging this, I found that the Buffer complete callback being called has an argument (GraphicEventArgs) that gets a geometry (polygon ring) shape from esri service. The points in the ring are of larger distance when we click on points near the pole. I am unable to get why the shape is getting distorted.

I had even copied the complete code from (http://help.arcgis.com/en/webapi/silverlight/samples/start.htm#BufferPoint) in the source code and it still produced elliptical shape.

Example of Polygon rings while trying to create a circle around 500km radius:
1) When user clicks on point near to center of map:
Longitude:23 and Latitude:10
--> One of the point in GraphicEventArgs was: X=27.093424764653, Y=8.03057538034022
Aprrox distance between points = 496 km (~500km)

2) When user clicks near pole.
Longitude: 23 and Latitude: 80
--> One of the point in GraphicEventArgs was: X=49.7117238764841, Y=81.00818899076
Approx distance between points = 2972 km (Leads to horizontal increment and creation of ellipse shape).

Please guide me so that I can resolve the issue....