added coordinate methods for matrix

WindStressPRM/Utils/Matrix.cs

@@ -8,7 +8,19 @@ namespace WindStressPRM
     /// </summary>
     /// <typeparam name="T"></typeparam>
     public class Matrix<T>
-    {
+    {   
+        /// <summary>
+        /// origin coordinates of matrix. This must be top left corner
+        /// </summary>
+        public Coordinate Origin { get; set; }
+        /// <summary>
+        /// get coordinate of cell at index
+        /// </summary>
+        /// <param name="index"></param>
+        /// <returns></returns>
+        public Coordinate CoordinateAt(Index index) {
+            return new Coordinate(Origin.X + index.Row*Size.Width, Origin.Y - index.Col*Size.Height);
+        }
         /// <summary>
         /// AffineCoefficients for matrix from raster projection
         /// </summary>