FIGURE 1.1 Subjective Landscape. Developed in painting, “Landscape” became a popular aesthetic practice for hikers, walkers, and other nature lovers but also an everyday viewing habit. The visual field defines the dimension of a landscape that is instantly composed by the viewer and gets transformed by changing viewing direction or position. This image visualizes the momentary landscape of a viewer not in motion but covering a visual angle of 360°. (Courtesy of T. Hauck.)