ploting the marker on google map from database

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ASP.NET

SQL-Server

I have to plot the point or marker on google map from sql server table. below code can plot a point from database but it only point the last one stored latitude & longitude value in database..
Latitude Longitude is my column name in database...i use literal tag for storing value from database..
this is my aspx page...

<script type="text/javascript">
        var map;
        function initialize() {
            if (GBrowserIsCompatible()) {
                map = new GMap2(document.getElementById("map"));

                var lat = <asp:Literal ID="ltrLat" runat="server" />;
                var lng = <asp:Literal ID="ltrLng" runat="server" />;
                var center = new GLatLng(lat, lng);

               map.setCenter(center, 15);
               map.setUIToDefault();

               var marker = new GMarker(center);
               map.addOverlay(marker);
               marker.openInfoWindow("Here");

           }
       }
       </script>

this is cs page load events of above aspx page through which it take value from database..
please improve the code which show all marker on map from database

SqlConnection conn = new SqlConnection("Data Source=.\\SQL2005;Initial catalog=fitnessapp;User Id=sa;Password=123456");

 String qry = "select Latitude,Longitude from loglatMaster";
        SqlCommand cmd = new SqlCommand(qry, conn);
        conn.Open();
        SqlDataReader dr = cmd.ExecuteReader();
        if (dr.HasRows)
        {
           
                DataTable dt = new DataTable();
                dt.Load(dr);
              
                for (int i = 0; i < 2; i++)
                {
                Literal ltrLat = (Literal)FindControl("ltrLat");
                Literal ltrLng = (Literal)FindControl("ltrLng");

               
                ltrLat.Text = dt.Rows[i]["Latitude"].ToString();
                ltrLng.Text = dt.Rows[i]["Longitude"].ToString();
               
            }
        }
    }