The Spline Stacked Area chart is a variation of the Spline Area chart. The areas are stacked so that each series adjoins but does not overlap the preceding series.
Also can be used for data modeling in that it takes a limited number of data points and interpolates the intervening values. This chart type allows the entire surface area for all sequences to be displayed at one time.
In the example below the actual meters drilled area is compared to and stacked above the YTD monthly target drill meters area.