In a method of computing sample data to render a graph element, first sample data is computed to render a first graph element type. A second indicator is received that indicates a second graph element type to present overlaid with the first graph element type. Second sample data is computed to render the second graph element type. Third sample data is computed to render a second instance of the first graph element type. The second instance of the first graph element type is rendered overlaid with the second graph element type using the computed second and third sample data. A first number of points computed for the second sample data is the same as a second number of points computed for the third sample data. A common axis is used, and the first number of points is determined based on a data type of the common axis.