The image was obtained from the above reference. It can be created using paintbrush. Different colors are used to represent the various metabolic cycles. For example, the carbohydrate metabolism is represented by shades blue as shown in the map, dark blue represent carbohydrate metabolism and sky blue represent complex carbohydrate metabolism. Different shades of green represent Lipid metabolism.
Shades of orange is used to represent protein metabolism.
The pixels represent metabolities. The key to the map is embeded in the map. Note that there is no key for each pixel. Therefore, this map is geared for an audience with intense biological knowledge. However, the map even though intense with information allows to viewer to see that metabolism is a very complex process.