From: The World In Your Head by Steven Lehar

Fig. 4.9 (A) An azimuth/elevation/vergence representation maps the infinity of three-dimensional Euclidean space into a finite perceptual space. (B) The deformation of the infinite Cartesian grid caused by the perspective transformation of the azimuth/elevation/vergence representation. (C) A view of a man walking down a road represented in the perspective distorted space. (D) A section of the spherical space depicted in the same format as the perspective distorted space shown in Fig. 4.7.