This video illustrates the activity of world's commercial shipping fleet over a period of time. Each dot represents an individual ship's movement. Other screens show each ship's complete route for the time period covered, illustrating the tremendous extent and reach of commercial traffic on the waterways of the world. Colored dots represent different types of ships: Red represents tankers transporting petroleum products. Blue dots are carrying "dry bulk" products such as coal and ores. Yellow dots represent ships carrying manufactured goods.
Textbook Reference: page 330