Frames and missing values
How the Axis field becomes frames, how a date axis can be rolled up before it animates, and what happens where data is absent.
Frames
Each distinct value of the Axis field becomes one frame. Frames are sorted by the field's own sort order — dates chronologically, numbers numerically, text by its sort column — and the animation plays through them in that order.
Axis grain
A date axis can be rolled up before it animates, so seven hundred daily rows can be watched as twenty-four monthly frames without changing the model.
| Setting | Options |
|---|---|
| Grain | Auto, Day, Week, Month, Quarter, Year |
| Aggregate | Sum, Average, First, Last, Minimum, Maximum |
Missing values
When a category has no row for a period, the visual has to decide what to draw. Four behaviours are available, and the right one depends on what the absence means.
| Setting | Behaviour |
|---|---|
| Exclude from frame (default) | The period is genuinely absent. |
| Treat as zero | Substitutes zero. |
| Carry forward | Holds the last known value. |
| Interpolate | Draws a straight line between the known values either side. |
On Exclude, a category that stops having rows ends where its data ends. On a line chart the line stops at its last real point rather than dropping to zero, so a fall that was never in the data is not drawn.