Combo charts (also called combination or mixed charts) overlay two or more chart types, typically bars and lines, on the same axes. They are ideal for comparing related metrics measured on different scales, such as revenue (bars) vs. profit margin (line), or showing both actuals and targets simultaneously. viz42 generates combo charts that clearly distinguish each series type.
Mermaid's xychart-beta uses a single Y-axis. For true dual-axis combos, viz42 normalizes the data to fit one scale and labels both metrics in the chart title.
The most common combination is bars and lines. viz42 supports mixing bar and line series on the same chart for effective multi-metric comparison.
Use combo charts when you need to compare metrics that have different units or scales (e.g., revenue in dollars and growth in percent) on the same time axis.