Marey.Plot 0.2.0

Marey.Plot

The chart API of Marey, a dimensionally-typed visualization system for F#. This is the package most people install.

#r "nuget: Marey.Plot"
#r "nuget: Marey.Backend.Svg"

open Marey

let t = Array.init 24 (fun i -> float i * 0.4<s>)
let x = t |> Array.map (fun t -> 0.5 * 9.81<m/s^2> * t * t)

Chart.line U.second U.metre t x
|> Chart.withTitle "Free fall"
|> Chart.toSvg SvgBackend.render "fall.svg" (Chart.size 800.0 500.0)

That prints an x axis reading t [s] and a y axis reading x [m] with nothing configured. The scale, the domain, the SI prefix, the tick values, the tick labels and both axis titles are derived from the two unit witnesses. x is never annotated as a length — the compiler works that out — and plotting metres against metres on these axes is a compile error.

What is in it

• Chart — twelve geoms: line, scatter, area, bar, errorbar, step, ribbon, tile, rect, segment, text, and box plots and violins by category. Most have an add* that layers onto the last panel, and Chart.Plain covers data that genuinely has no units.
• The plot encoding block — for data that is a table rather than two arrays. Declares x, y, colour, shape and size in one place, with each dimensioned channel checked against its witness.
• Channels. One colour or marker shape per category, with a legend that names the levels; or a colour or size driven by a quantity, which brings a colorbar labelled from its unit witness.
• Statistics — histogram, kernel density, ECDF, least-squares fit, and a five-number summary. The measures carry through: a fit of metres against seconds has a slope of type float<m/s>.
• Facets. facetWrap gives one panel per level of a key, over shared axes.
• Themes. Six, all measured against the colour validator below. Theme.tikz inherits the host LaTeX document's fonts.
• Palettes — Okabe–Ito, viridis, cividis, magma and an Oklab diverging ramp, with a colour-vision-deficiency and contrast validator that every shipped theme is checked against.
• A measure–arrange constraint layout, and the axis and legend compilers.
• Per-layer styling that survives a theme change where it was set explicitly and is recoloured where it was not, which is what makes withTheme safe to apply last.

No backend reference

Marey.Plot does not depend on a renderer. A backend is a function passed in at render time, which is why the same figure goes to SVG or to LaTeX without the figure knowing either exists. Install one:

• Marey.Backend.Svg — pure F#, zero dependencies.
• Marey.Backend.Tikz — tikzpicture source for LaTeX, with siunitx units.

Depends on Marey.Core and Marey.Units.

• The guide
• Examples