SDM Smart Pie Chart
The SDM Smart Pie Chart renders a composition as a pie, a donut, or a half-circle gauge — or, in its concentric type, as radial bars. Each category is a value of the Category field; each value of the Legend field adds a whole chart to a grid of small multiples.
Key Features
- Three shapes — full circle, top half circle and bottom half circle. A half circle is not a cropped pie: the whole series is laid out over 180°, so every slice keeps its share of the total
- Pie or donut — an adjustable inner radius turns the pie into a donut, which unlocks the center label
- Small multiples — one chart per legend value, with a cap on the number of charts per row; a partial last row stays centred
- Concentric rings — a second chart type: one ring per category, each starting at zero and scaled to the largest value, for magnitudes that do not add up to a whole
- Regex highlighting — pull one or more slices out of the crowd by exploding them, outlining them, or dimming the others
- Target line — a radial mark at the angle carrying a target value, as a value or as a percentage of the total
- Center label — the total, or any caption, in the hole of a donut
- Data-driven colors and logos — the Series Color field colors either the slices or the charts; the Logo field feeds the legend, the slices themselves (inside or outside) and the series titles
- Significance testing — up to three tests, each comparing every series to a reference series category by category on its shares, or to an external reference
- Cross-filtering — click or Ctrl+click a slice to filter other visuals
- Tooltips — category, value, share, base and custom tooltip measures on hover
- Series Threshold — a publication rule applied one small multiple at a time: a market whose smallest base falls short is flagged, or withdrawn and replaced by a message, while its neighbours keep being drawn
- Note — a caption box over the chart, with
%MIN(field)style formulas and an alert that fires under a threshold - Global Threshold — clears the chart on an empty dataset, or when a base is too small to be published
Data Wells
| Data Role | Description |
|---|---|
| Category | One slice per value |
| Values | The measure sliced by the pie |
| Legend | Splits the data into one chart per value, laid out as a grid of small multiples |
| Series Color | A measure or column returning a hex color, read per category or per legend value |
| Logo | A measure or column returning a base64 image, read per category (legend and slice logos) and per legend value (series titles) |
| Base | Sample size, required by the significance tests |
| Standard Deviation | Used by the significance test on means |
| Significance reference | Reference of an External reference significance test, as JSON — not drawn |
| Tooltips | Extra measures added to the tooltip |
Negative and missing values
A pie divides a whole, so a negative contribution has no angle to occupy: negative values are plotted as zero. They stay available to the significance test on means, which works on the raw value rather than on the share. Blank values are simply absent from the chart.
Formatting Cards
| Card | What it controls |
|---|---|
| Pie | Chart type, shape, hole, slice geometry, ordering, color target |
| Multiple Series | The grid of small multiples, and the ring geometry |
| Series Title | The caption above each small multiple |
| Data Colors | Per-slice or per-series colors |
| Highlight | Regex-driven emphasis of selected slices |
| Target Line | The radial target mark |
| Legend | Legend position, font and logos |
| Data Labels | Label content, placement and background |
| Center Label | Text in the hole of the donut |
| Significance | Statistical comparison to a reference series |
| Series Threshold | Flags, or withdraws, a single series whose smallest base falls short |
| Note | Caption box drawn over the chart, with formulas and an alert |
| Global Threshold | Clears the chart on an empty dataset or under a base threshold |