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16 changes: 3 additions & 13 deletions docs/transforms/interval.md
Original file line number Diff line number Diff line change
Expand Up @@ -14,18 +14,13 @@ There’s also an [**interval** scale option](../features/scales.md#scale-transf

The **interval transform** turns a quantitative or temporal *value* into a continuous extent [*start*, *stop*]. For example, if *value* is an instant in time, the interval transform could return a *start* of UTC midnight and a *stop* of the UTC midnight the following day.

The interval transform is often used for time-series bar charts. For example, consider the chart below of the daily trade volume of Apple stock. Because of the [barY mark](../marks/bar.md), the *x* scale is ordinal (*band*). And because the regularity of the data is not specified (*i.e.*, because Plot has no way of knowing that this is daily data), every distinct value must have its own label, leading to crowding. If a day were missing data, it would be difficult to spot! 👓
The interval transform is often used for time-series bar charts. For example, consider the chart below of the daily trade volume of Apple stock. Because of the [barY mark](../marks/bar.md), the *x* scale is ordinal (*band*). And because the regularity of the data is not specified (*i.e.*, because Plot has no way of knowing that this is daily data), every distinct value must have its own label, leading to crowding. If a day were missing data, it would be difficult to spot! 👓

:::plot https://observablehq.com/@observablehq/plot-band-scale-interval
```js
Plot.plot({
marginBottom: 80,
x: {
type: "band", // ⚠️ not utc
tickRotate: -90,
fontVariant: "tabular-nums",
label: null
},
x: {type: "band"}, // ⚠️ not utc
y: {
transform: (d) => d / 1e6,
label: "Daily trade volume (millions)"
Expand Down Expand Up @@ -66,12 +61,7 @@ The meaning of the **interval** mark option depends on the associated mark, such
```js
Plot.plot({
marginBottom: 80,
x: {
type: "band", // ⚠️ not utc
tickRotate: -90,
label: null,
fontVariant: "tabular-nums"
},
x: {type: "band"}, // ⚠️ not utc
y: {
grid: true,
transform: (d) => d / 1e6,
Expand Down