fixing shift_xy

rasters/raster_grid.py

@@ -537,10 +537,16 @@ def subset(self, target: Union[Window, Point, Polygon, BBox, RasterGeometry]) ->
         return subset
 
     def shift_xy(self, x_shift: float, y_shift: float) -> RasterGrid:
-        new_affine = self.affine * Affine.translation(x_shift, y_shift)
-        grid = RasterGrid.from_affine(new_affine, self.rows, self.cols, self.crs)
-
-        return grid
+        cell_width = self.cell_width
+        cell_height = self.cell_height
+        x_origin = self.x_origin + x_shift
+        y_origin = self.y_origin + y_shift
+        shifted_x_origin = x_origin + x_shift
+        shifted_y_origin = y_origin + y_shift
+        shifted_affine = Affine(cell_width, 0, shifted_x_origin, 0, cell_height, shifted_y_origin)
+        shifted_grid = RasterGrid.from_affine(shifted_affine, self.rows, self.cols, self.crs)
+
+        return shifted_grid
 
     def shift_distance(self, distance: float, direction: float) -> RasterGrid:
         x_shift = distance * np.cos(np.radians(direction))