An evaporation pan is used to hold water during observations for the determination of the quantity of evaporation at a given location. Such pans are of varying sizes and shapes, the most commonly used being circular or square.  The best known of the pans are the "Class A" evaporation pan and the "Sunken Colorado Pan". In Europe, India and South Africa, a Symons Pan (or sometimes Symons Tank) is used. Often the evaporation pans are automated with water level sensors and a small weather station is located nearby.