XY / Bubble Chart
An xy / bubble chart displays data points on a grid as semi-transparent circles of varying sizes ("bubbles").
Data Requirements
To use an xy / bubble chart a report query must produce at least two numerical columns to be interpreted as the X and Y coordinates of the data point. An optional 3rd numerical column can be used to represent the magnitude of the data point (and thus the size of the bubble on the grid). For example, a query result such as
| x | y | size |
|---|---|---|
| 1 | 1 | 1 |
| 2 | 2 | 2 |
| 3 | 3 | 3 |
can produce the following xy / bubble chart:
The values of any additional result columns (i.e. not used for X, Y or Size), which need not be numeric, are shown in the tooltips (if enabled) as additional context information.
Interactive Features
Tooltips
When hovering the cursor over a circle ("bubble"), a tooltip is shown with the data points coordinates, size and, if present, information from additional result columns.
Configuration
The following options are available for the visual configuration of an XY / Bubble chart:
- S, M, L, XL: Preset sizes for the axis and legend labels.
- Tilt X Axis: The X axis labels can be tilted by 45 degrees, which can be especially useful for longer labels.
- Legend: Whether a legend should be displayed next to the chart.
- Tooltip: Enables or disables tooltips when the cursor hovers over a circle / bubble.
Columns
The column configuration determines which result columns are used for X axis,
Y axis and size. Only one column can be used for the X axis, whereas
multiple columns can be used for the Y axis. Each column used on the Y axis
defines a set of values that are plotted on the grid and can be labelled and
colored differently.
When only a single Y column is used, an additional column can be used for
Color. The values of that column then determine the coloring of the data
points according to a chosen Color Palette.
Other additional columns must be set as hidden (-). The values of such columns
are automatically included in the tooltips of the data points, if tooltips are
enabled.
X Axis Options
The X axis can be configured with a title, displayed below the axis.
Y Axis Options
The Y axis can be configured with a title, displayed on the side of the chart, and a line width. If the linde width is greater 0, the plotted circles are connected with a line of the chose width.
Color Options
When only a single column is used for the Y values, an additional numeric column can
be assigned the Color semantic, which enables the color options. The values of
this "color column" are interpreted as weights that determine the coloring of the
individual data points: Lower values take a color towards the left of the chosen
color palette and larger values take a color towards the right of the chosen
color palette.
To shift the colors more towards beginning, center or end of the color palette,
specify custom values for the Color min value and Color max value. For
example, if the lowest value in the color column is 42, the corresponding data
point would normally get the color on the left-most side of the color palette gradient.
By specifying 0 as the Color min value, the data point with color value 42
would get a color assigned that is more towards the right of the gradient
(how far to the right depends on what the largest value appearing in the color
column, which will be assigned the right-most color of the gradient).
Size Options
By default, the sizes of the circles ("bubbles") that visualize the data points in the chart are distributed on a scale from 1 to 50. Thereby size 1 is assigned to the data point with the smallest value and size 50 is assigned to the data point with the largest value. All other data points are given a size proportional to that scale.
To customize the size of the data points, either narrow the default size range, or specify custom minimum / maximum values.
