Density chart

Use a density chart to show where the values of a sample cluster and how far they trail, with one curve per group.

Source

```chart
type: density
title: Replies cluster near seven minutes, with a long slow tail
subtitle: Minutes to first reply
data:
  inline:
    - {minutes: 3.1}
    - {minutes: 4.2}
    - {minutes: 4.8}
    - {minutes: 5.0}
    - {minutes: 5.3}
    - {minutes: 5.9}
    - {minutes: 6.1}
    - {minutes: 6.4}
    - {minutes: 6.6}
    - {minutes: 7.0}
    - {minutes: 7.2}
    - {minutes: 7.5}
    - {minutes: 7.9}
    - {minutes: 8.3}
    - {minutes: 8.8}
    - {minutes: 9.4}
    - {minutes: 10.1}
    - {minutes: 10.9}
    - {minutes: 12.0}
    - {minutes: 13.8}
    - {minutes: 15.5}
    - {minutes: 18.9}
encoding: {x: minutes}
axes:
  x: {label: Minutes to first reply}
```

Fields that matter

• type: density with encoding.x for the numeric field, one value per row
• encoding.color draws one curve per group; encoding.facet splits the chart into panels
• style.bandwidth sets the kernel bandwidth as a positive number; without it RichView uses Silverman’s rule of thumb and says so in the note under the chart
• RichView computes the curve (a Gaussian kernel estimate on 128 points, padded by three bandwidths either side), so every value in a readout is marked as derived
• A group with fewer than two distinct values is reported and not drawn; rows without an x are listed as excluded
• axes.x and axes.y set label, format and unit

A curve may show one existing recorded density evaluation near its sampled peak, at the readout’s precision. This is a derived sampled value, not an analytic maximum. Groups share a total budget of five labels, or three below 480 px of plot width; a value with no clear position stays unlabelled.

Interactions

• Hover or focus the chart to read the values at the nearest x; the crosshair snaps to the nearest observation.
• Click a legend entry to toggle a group when the chart has several.
• Zoom and pan on the x axis with brush, wheel, pinch, keys or double-click; Escape or reset returns to the full range.
• Open the Table view, Download PNG or CSV, or Expand the chart.