A depth chart shows the demand and supply of a specific stock, commodity or currency. To set up a Depth Chart you need two series, Bids (green area) and Asks (red area). The ticks along the vertical axis are the sum of all offers at that price or lower. The x-axis value is the price of the offer for that amount of orders. The Asks series sums all orders descending and the Bids series will sort the sum of orders ascending.