What to read from a heatmap
Check axes, color scale and source time first. Stronger color indicates relative size within the chosen scale. Whether that scale adapts automatically matters when comparing snapshots. The same shade need not mean the same absolute value across periods.
Separate price freshness from option-source freshness
A fast ATAS price connection does not automatically make the options source faster. Check GEX timestamps separately. A 0DTE filter changes the included options, so compare views with matching filters and a clear data basis.
When a level is translated from an index to a future, its price reference must remain clear. Missing or stale data does not express a neutral market opinion. It indicates unavailable or old information.
Preserve the view for review
Preserve the visible context and timestamp before the trade. Add the actual price response and your rule afterward. This allows the journal to distinguish context used at the time from an explanation selected after seeing the result.