Depth chart

Jana knows charts where moving right means moving forward in time. That habit would mislead her here. In a conventional Depth chart, price runs horizontally and order quantity vertically. Coinbase therefore distinguishes it from the historical price chart. This is the displayed supply of orders on one market, not a record of completed trades. The trading pair, exchange and snapshot time belong with the picture. [1]

Buyers place bids, stating how much they want and the highest price they will pay. Sellers place asks, specifying quantity and their minimum price. At a chosen price, the bid curve totals bids at that price or higher; the ask curve totals asks at that price or lower. With prices increasing to the right, the bid curve falls and the ask curve rises, as Kraken describes. When buying, Jana looks at the selling side: those are the offers she would use. [2]

Cumulative simply means added up as you go. A higher point on the ask curve already includes the cheaper offers before it. The new quantity at the next price level is therefore the difference between heights, not the new point’s entire height. Adding all the heights again would count the same offers repeatedly. Kraken distinguishes level quantity from the cumulative total. This comparison requires the same snapshot and price grouping. [2]

For BTC/USD, quantities can be shown in bitcoin or as their dollar value. The same offers then naturally produce different numbers. Kraken also allows changes to the price range and the direction of the quantity axis. Zooming in can make a small step prominent; grouping prices can combine several steps into a larger one. Jana needs matching units and settings for comparisons. Colour and filled area alone do not tell her how much she can buy. [3]

In an ordinary continuously traded book, the best buyer offers less than the cheapest seller asks. The difference is the Bid–ask spread. The gap between the curves represents a price difference, not missing time or a future price jump. Special trading modes exist: during an auction, Coinbase gathers orders and publishes indicative information. Buying and selling prices can overlap then. That snapshot cannot be read as ordinary continuously available quotes. [4]

A pronounced step is often called a buy wall or sell wall. It means more displayed orders are concentrated at that price. Their owners can still change or cancel them. CFA lists spoofing among manipulative practices: displaying misleading orders without a genuine intention to execute them. A large step alone does not establish that intention. Nor does it guarantee Support or Resistance, price areas where traders expect a fall or rise to stop. [5]

Jana may see few resting orders while many trades are happening: new orders can replace filled ones. CME illustrates this on futures, contracts for future settlement. The lesson helps distinguish an immediate stock from the flow of trades, but does not guarantee the same behaviour on a bitcoin exchange. The chart also omits hidden portions of orders and future cancellations. Its shape alone cannot establish how well a market can absorb trades without a substantial price move. [6]

Jana first checks the market, data age, axes and units. She then finds her purchase price ceiling on the selling side and reads the total quantity through that price, inclusive. She compares it with the Order book. Coinbase separates aggregated quantity from order count; a count of orders is not a bitcoin quantity. If the chart does not cover the prices she needs, the answer is unknown. Even a complete snapshot is only information: offers can change before her purchase executes. [3] [4]