Overlaid Contour Plot 

Contour plots are created by fitting a 3D surface function to a 3D scatterplot; the resulting surface contours (i.e., lines of identical "altitudes") are then projected onto the X-Y plane. Like Surface Plots, contour plots are used to examine relationships between the three variables in the plot. An overlaid contour plot projects multiple 3D surface contours onto the X-Y plane. This type of plot is important within industrial settings in order to visualize the results of an experiment with multiple and sometimes competing responses.

For example, a typical problem in product development is to find a set of conditions, or levels of the input variables, that produces the most desirable product in terms of its characteristics, or responses on the output variables. Since each response in the process is important you need to optimize all responses simultaneously as opposed to one at a time. As an example, you might need to maximize the yield of a product and minimize the cost to manufacture the product. The problem is to select the levels for the input variables which find the best compromise. These problems can be addressed using Overlaid Contour Plots.

Such problems can also be addressed with the Experimental Design module using Response/desirability profiling.

The light blue region is the region that satisfies the criteria of both responses.