It is an analytical drawing tool created by WD Gann, used to identify price breakouts and price, time movements between highs and lows. Gann Fan contains series of lines named angles. These angles are overlaid on price charts to display prospective support and resistance levels. The resulting image advantage the experts to envisage price change in market.
The Gann Fan ideology is centered on concept that market moves from angle to angle and when angle is wrecked, price move towards next one. Gann Fan draws series of angle but 45 degree is believed to be most important one, which signifies one unit of price for one unit of time. When market touches an equivalent unit of price and time, change in market is expected. Gann Fan believe that trend line at or above 45 degree represents bullish trend while below 45 bearish. It allows users to draw 9 angle to identify market direction.