Charts
Scientific charts
Shapes a business chart cannot express: a phase portrait, a field of arrows, a spectrogram, a ternary composition. All of them take prepared data, and the one transform that is unavoidable — a streamgraph's layout — is the engine's and is named in the contract.
More than three dimensions
Parallel coordinates stay readable where a scatterplot matrix stops being: every axis is independent, so an observation is a polyline through its own values, and a crossing is a real trade-off.
Parallel coordinates
Sixty synthetic strategies across six axes. Invert an axis when lower is better.
Geometry
Ternary compositions, polar histograms and vector fields. Each one states its coordinate convention, and the tooltip prints the value the caller supplied rather than a re-derived one.
Ternary
Three shares that sum to one. A point whose shares do not sum to one is drawn at its normalised position, and the tooltip reports the shares it was given.
Polar rose
Nightingale rose: the radius is the measurement, the angle is only the category.
Wind rose
A stacked polar histogram — a wind rose for speed bins per direction.
Vector field
An arrow per sample, at the magnitude supplied. Scale is the caller's explicit choice and is reported in the tooltip.
Density and spectra
Contours, hexbins and spectrograms all answer 'where is the mass'. The rings, the bins and the samples are computed upstream; LUC owns the geometry, the ramp and the tooltip.
Contour
Iso-lines of a sampled saddle. The level is drawn on the line, so two adjacent contours are distinguishable without a legend.
Hexbin
Pre-binned hexagons at a radius in data units, so the geometry matches the bin at any zoom.
Spectrogram
Time against frequency with a fixed decibel range, so two spectrograms are comparable. Progressive rendering keeps a long capture responsive.
Flow and many distributions
A theme river shows composition over time as one shape; a ridgeline stacks many distributions along one axis. The vertical offset is a drawing transform, never a value change — which is why it is capped.
Theme river
The band layout is the engine's, because it places the caller's numbers rather than deriving them.
Ridgeline
Overlap is capped at 1 so one row can never fully hide the one beneath it.