Relationship
Surface chart
- Relationship
What it shows
Two inputs and one output as a landscape. Rarely the clearest option.
When to use it
Use a surface to explore a continuous response across two numeric inputs when the third value is genuinely measured or modelled.
Worked example
Visualise simulated production cost across production volume and fuel price. The height represents cost, not a third independent category.
Data required
A sufficiently regular X-Y grid, Z values, units, interpolation method and treatment of missing combinations.
Checks and common mistakes
Perspective can hide valleys and create false peaks. Check whether interpolation invents detail between sparse measurements.
More accessible alternative
A heatmap or contour plot with a labelled legend is usually easier to compare and more accessible.