The market is composed of time, price, and volume.
Volume is generated by the interaction of time and price.
During each trading session a value area is usually established as the market uses price-probes which move, alternatively, too high and too low in order to create TPOs that seek the trading activity of market participants. Since many market profile analyses require such volume information, they can be conducted for only these markets. There are two types of value area. The following market behavior is easily-observed. When a market opens within the range of the previous day's value area, the first time the high or low of that value area is approached, it will be resistance or support.