Market depth heatmap

What it is

A market depth heatmap is a color-coded visualisation of historical resting order book quantities over time. It's typically drawn as a horizontal price-by-time grid: the vertical axis is price, the horizontal axis is time, and each cell's color intensity encodes how much resting size sat at that price at that moment.

Where the DOM ladder shows you the order book right now, the heatmap shows you the order book over the last minutes or hours — a continuous picture of where liquidity was placed, where it persisted, where it got pulled, and where it got hit.

The visual is intuitive once you've seen one: bright horizontal bands mark price levels where significant resting size lingered for a sustained period; faint regions mark thin liquidity; sudden disappearances of brightness mark order pulls; sudden brightness onsets mark new size being added.

Why it matters

Heatmaps make persistent liquidity visible in a way that the raw DOM does not. The DOM shows the current snapshot; the heatmap shows the history. Several useful reads only emerge from the time dimension:

• Persistent walls that have been sitting at a price for hours behave differently from walls that just appeared.
• Liquidity that gets repeatedly hit but refills tells you somebody is defending a level.
• Liquidity that vanishes the instant price approaches signals provision that isn't real defense.
• Asymmetric long-term build-up of size on one side hints at structural inventory.

For traders combining order flow with depth, the heatmap is the cleanest way to overlay liquidity context onto a chart without trying to mentally reconstruct order-book history from a moving ladder.

How traders use it on Sierra Chart

Sierra Chart provides depth heatmap rendering via its Market Depth Historical Graph, driven by the platform's persistent recording of the order book. The heatmap is typically displayed as an overlay on a price chart or as a dedicated chart with price on the Y-axis and time on the X-axis.

Most traders run the heatmap as a context layer rather than a primary signal generator — it sits behind their footprint or candlestick chart and provides background information about where size has been resting. Reading the heatmap in isolation, without a price-action overlay, is rarely actionable.

Common patterns / pitfalls

• Heatmap intensity scales need to be calibrated per instrument. The same color thresholds that work on ES will be useless on a low-volume contract.
• Depth heatmaps capture visible resting size only. Iceberg liquidity is invisible to them.
• Persistent bands at round-number prices are common and often less meaningful than persistent bands at structural levels (prior POC, value area edges).
• Heatmap reads degrade fast in thin overnight conditions or low-volume contracts.
• A heatmap is context, not a trigger. The trade decision still comes from price action, footprint, or another active signal — the heatmap tells you whether the conditions support it.

Related SCS studies

Market Depth Manager extends the platform's depth tooling with additional views and controls aimed at making heatmap and depth analysis more practical during live trading.