Chart Specifications

Explains chart specifications

Differences between XY Charts and XYZ Charts

Bubble charts and scatter plots can be created using either XY charts or XYZ charts, but the data aggregation methods for drawing the charts differ.

Dimensions and Metrics

Chart data aggregation uses the concepts of dimensions and metrics.

• Dimension: Values used to group data. Categories, dates, etc. - determines "what to group by"

• Metric: Aggregated numerical values. Sums, averages, counts, etc. - determines "what to measure"

In SQL terms, dimensions correspond to columns used in GROUP BY, while metrics correspond to columns calculated using aggregate functions like SUM() or COUNT().

Differences in Aggregation Methods between XY Charts and XYZ Charts

Chart Type	Dimension	Metric
XY Chart	X-axis	Y-axis
XYZ Chart	X-axis, Y-axis	(Z-axis)

For XY Charts

The X-axis becomes the dimension, and the Y-axis values are aggregated as metrics.

Example: Displaying "Monthly sales totals" as a line chart

• X-axis (Dimension): Month

• Y-axis (Metric): Total sales value

For XYZ Charts

Both the X-axis and Y-axis become dimensions, and the Z-axis values are aggregated as metrics.

Example: Displaying "Sales totals by product category × region" as a heatmap

• X-axis (Dimension): Product category

• Y-axis (Dimension): Region

• Z-axis (Metric): Total sales value

Differences by Chart Type

Whether you create bubble charts or scatter plots as XY charts or XYZ charts affects the data aggregation method and rendering results.

• Scatter plot in XY chart: One plot per X value

• Scatter plot in XYZ chart: One plot per combination of X value and Y value

X-Axis Specifications for XY Charts and XYZ Charts

In XY charts and XYZ charts, different types of axes are internally selected based on the data type of the data specified for the X-axis.

• When date/datetime type data is specified, a datetime axis is generally used, but for XYZ charts with heatmaps selected, a categorical axis is used

• When numeric type data is specified, a numeric axis is used in XYZ charts, but in XY charts, either a categorical axis or numeric axis is used depending on the render type specified in the series

  • For XY charts, a numeric axis is used when the series is "Point", "Bubble", or "Line"

    • A categorical axis is used when "Bar" or "Area" is specified in any series

Chart Type	X-Axis Classification
XY Chart ("Point", "Bubble", "Line")	Categorical axis or Time axis or Numeric axis
XY Chart (others)	Categorical axis or Time axis
XYZ Chart (excluding heatmaps)	Categorical axis or Time axis or Numeric axis
XYZ Chart (heatmap)	Categorical axis

Categorical Axis

In a categorical axis, even if the specified values are numeric or date/datetime types, they are rendered as discrete values at equal intervals.

Specifying Axis Upper and Lower Limits

When specifying upper or lower limits for a categorical axis, the specified values are treated as indices of the data order (0th, 1st, 2nd...).

Index	X-Axis Value
0th	1
1st	10
2nd	20
3rd	30
...	...
10th	100

In this case, if you set the axis upper limit to 10, data up to the 10th index will be displayed, which means X-axis values up to 100 will be shown.

Time Axis

In a time axis, the specified date/datetime type data is rendered as a continuous time series.

• Axis labels are dynamically determined based on the specified date/datetime data

• When datetime type data with timezone is specified, it is converted to the timezone specified in the browser for rendering

  • Axis labels are displayed based on the time zone specified in the browser. Therefore, if the browser's time zone does not match the time zone of the data, the axis labels and data labels will be drawn out of alignment

  • Converting to a date-time format without a time zone can also prevent the browser's time zone from affecting the date and time

Numeric Axis

In a numeric axis, the specified numeric type data is rendered as continuous numeric values.