United States at Night - - Nightviews Map: The Night Views perspective emphasizes built-up areas, shown as if they were city lights glowing at night, with just enough moonlight to reveal landforms in the background. This narrow focus gives a remarkably clear picture of the pattern of settlement. The effect is pretty close to actually being a captured record of the illumination. We are showing impervious surfaces, whose variable density distinguishes commercial and industrial uses from lower-density residential areas. The dark blue shaded relief background highlights the settlement pattern, the important theme of these maps.