The following figure shows the data structure of a 3-D surface graph.
The data structure of a 3-D surface graph is as follows:
A group is represented by an imaginary line running from the left wall to the lower right edge of the graph. It is labeled by a Z tick label, such as 1999.
A series is represented by an imaginary line running from the right wall to the lower-left edge of the graph. It is labeled by an X tick label, such as Germany.
In a 3-D surface graph, the colors in the surfaces help to identify the value of that area of the surface. The legend shows the colors and their corresponding values.