Heatmap
Status: EARLY Draft/Proposal
Heatmaps are used to show the magnitude of a phenomenon as color in two dimensions. The variation in color may give visual cues about how the phenomenon is clustered or varies over space.
Heatmap Rows (HeatmapRows)
Version: 0.0
The first field represents the X axis, the rest of the fields indicate rows in the heatmap.
The true numeric range of each row can be indicated using an "le" label. When absent,
The field display is used for the row label.
Example:
| Type: Time Name: Time | Type: Number Name: Labels: {"le": "10"} | Type: Number Name: Labels: {"le": "20"} | Type: Number Name: Labels: {"le": "+Inf"} |
| 2022-05-24 18:19:51 | 6 | 7 | 8 |
| 2022-05-24 18:19:51 | 6 | 7 | 8 |
| 2022-05-24 18:19:51 | 6 | 7 | 8 |
Note: Timeseries wide can be used directly as heatmap-rows, in this case each value field becomes a row in the heatmap.
Heatmap cells (HeatmapCells)
Version: 0.0
In this format, each row in the frame indicates the value of a single cell in a heatmap. There exists a row for every cell in the heatmap.
Example:
| Type: Time Name: xMax|xMin|x | Type: Number Name: yMax|yMin|y | Type: Number Name: Count | Type: Number Name: Total | Type: Number Name: Speed |
| 2022-05-24 18:19:51 | 100 | 1 | 1 | 1 |
| 2022-05-24 18:19:51 | 200 | 2 | 2 | 2 |
| 2022-05-24 18:19:51 | 300 | 3 | 3 | 3 |
| 2022-05-24 18:19:52 | 100 | 4 | 4 | 4 |
| 2022-05-24 18:19:52 | 200 | 5 | 5 | 5 |
| 2022-05-24 18:19:52 | 300 | 6 | 6 | 6 |
This format requires uniform cell sizing. The size of the cell is defined by the columns in each row that are chosen as the xMax|xMin|x and the yMax|yMin|y. We can see that the Number column(yMax|yMin|y) increases by 100(each cell is roughly 100 higher than the previous cell on the y axis) for each row containing a similar Time value(these stacked cells all have roughly the same location along the x axis). This produces a uniform cell size.
Note that multiple "value" fields can included to represent multiple dimensions within the same cell.
The first value field is used in the display, unless explicitly configured
The field names for yMax|yMin|y indicate the aggregation period or the supplied values.
- yMax: the values are from the bucket below
- yMin: the values are from to bucket above
- y: the values are in the middle of the bucket
Sparse heatmaps
When both min+max fields exist for X and/or Y, the dimension does not need to be uniformly distributed. For high resolution with many gaps this approach can be smaller and more efficient.