Relative Volume or RVOL is an indicator used to help determine the amount of volume change over a given period of time. It is often used to help traders determine how in-play a ticker is. General rule of thumb is the higher the RVOL, the more in play a stock is. I myself like to use it as a substitute of the volume indicator itself.
Basic Calculation: Relative Volume = Current Volume / Average Volume
Crossover Signals: Any time there is a volume spike which causes a crossover of the user set'Smoothed Moving Average' or 'Threshold' a green/red dot will appear at the top. The color of the dot is dependent on closing of the candle. Therefore it does not necessarily mean price will continue in that direction since volume spikes often happen in peaks or valleys.
Threshold: The level at which custom alerts and signal can be set. The higher the value, the more volume required to trigger.
Built in Alerts: You can set custom alerts for the crossovers of the adjustable threshold, or the average RVOL band.