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Heatmap Chart

The heatmap packs X and Y into a flat grid of colored cells. Each cell shows a value and a color — spot high/low combinations at a glance across the full matrix.

Use heatmaps when you have two categorical dimensions. A z-axis is optional: without z you get a single-gradient matrix; with z each cell shows the sum of its z-series values on the same gradient.

Dimension Role
XAxis Columns of the grid
YAxis Rows of the grid
ZAxis Folded into each cell: cell value = Σ z, colored on a shared gradient

A cell with multiple z-series shows their summed value. Hover to see the per-z breakdown in the tooltip.

Classic heatmap: one value per X × Y cell, colored on a continuous gradient with a visualMap scale. No z-series — magnitude as color.

Terminal window
vizb heatmap data.csv -g category,metric -p x,y -o out.html

Z values are folded into each cell rather than rendered as depth. Each cell displays Σ z and is colored on the same continuous gradient as the 2D heatmap. Hover a cell to see the individual z-series breakdown with colored dots. Toggle z-series in the legend — cells recompute live.

Terminal window
vizb heatmap data.csv -g category,metric,group -p x,y,z -o out.html

These settings apply to heatmap charts:

Setting CLI flag UI toggle Notes
Sort --sort asc|desc Sort control Orders the matrix axes
Labels --show-labels Show labels Shows the summed value inside each cell
Swap --swap yx Axis switcher Swaps X and Y axes

Override settings for just the heatmap without affecting other charts:

Terminal window
# Show per-cell labels
vizb heatmap data.csv -g category,metric,group -p x,y,z -l -o out.html
# Sort the axes descending
vizb heatmap data.csv -g category,metric,group -p x,y,z --sort desc -o out.html