Volume bars are a representation of the transactions that have taken place on the best bid and ask. They are shown at the bottom of the chart. The color corresponds to the aggressor side: red is for sell side, and green is for buy side.
When a volume bar is shown in two colors, it means that the volume accumulated for this bar contains both buy and sell aggressor side trades. Zoom in onto this bar to see individual trades for both sides. This will also work for a single-color bar: in this case, zooming in onto it will display individual trades of the same side.
The height of each bar is proportionate to the cumulative volume of all trades this bar consists of. You can estimate the volume for each bar using the red reference line that appears when you hover your mouse over the volume bars. The indication of volume correspondent to this level is located on the left. Drag and drop the red line to proportionally change the height of each volume bar.
To customize volume bars:
1. Right-click on a volume bar and choose Volume Settings. This will open the Studies configuration menu with the Volume Bars tab active.
2. Select the desirable bar width in the Bars width dropdown. Note that the bar width is proportionate to the volume aggregation period.
3. In the Volume display options area, you can specify the following:
- Coloring mode. Choose Solid to display the relative size of buy and sell aggressor trades as a combo of two solid colors. Choose Gradient to use a gradient scale for the relative size of buy and sell aggressor sides.
- Calculation mode. Choose Total volume to display the total volume traded during the aggregation period. Choose Volume delta to display the difference between buy and sell order sizes.
4. In the Clustering dropdown, select the desirable mode of volume bar clustering:
- Smart. Using a proprietary Bookmap algorithm, the system aggregates several adjacent bars into a single one. This algorithm takes into account both VWAP and time of execution. Drag the slider on the right to make this clustering more or less pronounced.
- Time. The bars are shown in equal intervals with their height being proportionate to the aggregated transaction volume. You can select the desirable aggregation period from the dropdown to the right.
- Volume. The system shows a new volume bar after a specified volume accumulates. You can specify the desirable cumulative volume using the combo-box on the right.
Note: A bar may accumulate more contracts than the specified value. This happens when the size of the last trade exceeds the limit value. For example, if the specified volume limit is 100 and the volume bar consists of two single consecutive trades of 50 and 100 in size, the volume bar will show 150 contracts traded, not 100.
- Aggregation by price. All trades are accumulated in a single volume bar as long as they happen at the same price level, regardless of the aggressor side.
5. You can have both volume bars and volume dots use the same clustering mode. To do so, either click Inherit from dots so that bars inherit the mode from the dots or click Apply to dots to make the dots use the same mode as the bars do.
6. To restore volume bar settings to factory defaults, click Restore.
7. To hide volume bars, deactivate the checkbox to the left of Volume bars on the left-hand panel. To make it visible again, activate this checkbox.