An important part in the training of airplane pilots is the flight simulator. It has a real cockpit, but what you see outside the windows is computer imagery. As you take a right turn, the terrain below changes accordingly; as you dive downwards, it comes closer to you. When you change the (simulated) position of your plane, the simulation software must recompute a new view of the terrain, clouds, or other aircraft. This is done through the application of 3D affine and linear maps. 1 Figure 12.1 shows an image (hat was generated by an actual flight simulator. For each frame of the 172simulated scene, complex 3D computations are necessary, most of them consisting of the types of maps discussed in this section. A flight simulator scene from the NASA/Langley web page <uri>http://bigben.lare.nasa.gov/ntsim/ntsim.html</uri>.