Cloud cover over the Earth is measurable using several techniques, including a trained observer, some automated ground-based system, or an aircraft or a space platform. These three views of the three-dimensional cloud scene differ in a number of ways. The surface-observing system is generally fairly close to the clouds (<10–15 km), whereas the satellite is far removed from them (>1000 km). The complementary nature of the bird's eye and worm's eye views of a multilayered cloud scene and the distinct and complementary advantages of high-quality cloud texture/type retrieval from the surface and aircraft and excellent spatial and temporal coverage by satellites have prompted proposals for cloud climatologies combining conventional and satellite retrievals. This requires careful study of the nature of conventional (surface-based) cloud observation techniques.