The researchers studied different lighting indicators in urban areas to find one that accurately represents how people and nature look under different lighting conditions. They tested three indicators at a pedestrian street in Chongqing and found that the ratio of vertical illuminance to horizontal illuminance is similar to the ratio of average cylindrical illuminance to horizontal illuminance. These ratios change depending on where you measure them, peaking at the center of the street between two streetlamps. The ratio of vertical illuminance to semi-cylindrical illuminance showed less variation and is suggested as a better indicator for urban lighting quality.