[ternary-density] Ternary Density Plot for Compositional Data

[MarkusNeusinger]

Ternary plot with density heatmap overlay for visualizing compositional data distributions. Combines the three-component ternary diagram with kernel density estimation to show where data points concentrate in the composition space.

[claude]

✅ Spec ID: ternary-density

Rationale: Combines ternary plot visualization with kernel density estimation to show concentration patterns in compositional data. This is a distinct variant from ternary-basic which shows individual points.

Add label approved to begin generation.

[github-actions]

✅ Specification Ready: ternary-density

PR: #3699

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specification.md

ternary-density: Ternary Density Plot

Description

A ternary density plot combines a three-component ternary diagram with kernel density estimation to visualize where compositional data concentrates. Instead of showing individual points, this visualization uses a heatmap overlay to reveal the underlying probability distribution of compositions, making it ideal for identifying clusters, modes, and patterns in large compositional datasets.

Applications

• Analyzing sediment composition distributions across geological samples (sand/silt/clay)
• Visualizing alloy mixture preferences in materials science research
• Identifying common flavor profiles in food science (sweet/sour/bitter ratios)
• Understanding market positioning patterns among three competing attributes

Data

• component_a (numeric) - Proportion of first component (0-100%)
• component_b (numeric) - Proportion of second component (0-100%)
• component_c (numeric) - Proportion of third component (0-100%)
• Size: 100-5000 points ideal for density estimation; fewer points may yield sparse density
• Constraint: All three components must sum to 100% (or a constant total)

Notes

• Use a perceptually uniform colormap (viridis, plasma) for the density overlay
• Grid lines should be visible beneath the density layer with appropriate transparency
• Each vertex should be clearly labeled with component names
• Consider showing contour lines at key density levels for easier interpretation
• Bandwidth selection for KDE affects smoothness; auto-selection methods work well for most cases

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[github-actions]

🚀 Specification Merged!

Specification: ternary-density
PR: #3699 (merged)

The specification is now in main and synced to PostgreSQL.

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Available libraries: matplotlib, seaborn, plotly, bokeh, altair, plotnine, pygal, highcharts, letsplot

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