Variants
Three-variable carpet plot (cheater plot)
A carpet plot with two independent variables and one dependent variable is often called a cheater plot for the use of a phantom "cheater" axis instead of the horizontal axis. As a result of this missing axis, the values can be shifted horizontally such that the intersections line up vertically. This allows easy interpolation by having fixed horizontal intervals correspond to fixed intervals in both independent variables. The horizontal shift must sometimes be adjusted in order to eliminate or mitigate overlapping. Depending on the data being depicted, eliminating overlapping is not always possible. The common solution is to split the plot into two carpets.Four-variable carpet plot (true carpet plot)
Instead of using the horizontal axis to adjust the plot perspective and align carpet intersections vertically, the horizontal axis can be used to show the effects on an additional dependent variable.Schneider, Markus. ''How to Generate Carpet Plots: A Guide to Creating Visual Trade Studies''. In this case the perspective is fixed, and any overlapping cannot be adjusted. Because a true carpet plot represents two independent variables and two dependent variables simultaneously, there is no corresponding way to show the information on a conventional contour plot or 3D surface plot.Carpet plot with isolines
To add an additional dependent variable, isolines that are a function of the two independent variables can be added within the carpet to create a contour plot in the carpet domain. Contours can be added to cheater plots as well as to true carpet plots.Lattice plot
The effects of an additional independent variable can be visualized by multiple carpets on the same plot corresponding to different values of the third independent variable. If the intersections are connected, a lattice appears. For an intermediate value, a whole carpet can be interpolated using the lattice lines. This technique may result in too much overlapping of carpets in a true carpet plot but is always possible for a cheater plot because the separation of the additional carpets can be adjusted on the phantom horizontal axis.References
External links
{{Commonscat, Carpet plot, Carpet plots