http://www.dailygalaxy.com/my_weblog/2011/06/-image-of-the-day-the-real-earth-how-it-looks-from-space-with-gravity-field-in-effect.html
Why do gravity variations exist at all? Isn't gravity a constant? And what is the point of the odd shape if the colors already differentiate the different gravitational variations? Is that really how lumpy the Earth is?
Well, to explain why gravity might be different on a theoretical, round, earth, we must accept gravity. A concept which states that masses in three dimensional space will accelerate toward each other in the fourth dimension of time proportional to their mass and distance. Gravitation might be altered on such a hypothetical fiction, if mass was not evenly distributed through't the volume by means of density pockets. In this flawed theory big g G is a constant to do with the interactions of force distance time and mass and never changes, little g g is an approximation used for times when you only care 99 parts out of 100 how you fall to the floor. The theory then begins to break down and lead to all sorts of nonsense like things fall slower on tall mountains.
You are basically looking at a simulation someone ran assuming the world was a giant ball of swiss cheese. The colors represent the freshness of region of cheese in question.