trouble using image map control

 hi
 i'm learning how to use image maps to create hotspots for a geographical site i'm creating. I used a circular hotspot to test it out. Problem is it's not working. I think either its the grid and ruler I used to get the X and Y co-ordinates or i messed up somewhere in the code. Is there an easier way of getting the coordinates in an image ang genarally using image map control?
Design code
 <body>
<form id="form1" runat="server" >
 <div>
<asp:ImageMap ID="ImageMap1" ImageUrl="image/UG.gif" runat=""server>
<asp:CircleHotSpot X="400" Y="450" Radius="10" NavigateUrl="~/Default2.aspx" HotSpotMode="Navigate" AlternateText="Masindi"  />
</asp:ImageMap>
</form>
<body>

...