A 2D contour chart displays only contour data, but a 3D surface chart can display both contouring and elevation data. Normally, all data in a data grid represents both contouring and elevation. If you choose to use separate contour data, the charting utility will divide the data grid, vertically between columns, into two equal sub-ranges of data. The left sub-range contains elevation data, and the right sub-range contains contouring data.

You can choose to separate contour data by selecting the Separate Contour Data check box on the Elevation tab.

If you choose to separate contour data, a surface chart will display surface contours that do not necessarily conform to the shape of the surface. For example, a surface chart displaying separate contour and elevation data might depict metal grades at different elevations.