In Tableau, multi-axis and same-axis refer to different approaches for displaying multiple measures (data variables) in a single visualization. Here’s a brief explanation of each:
Multi-Axis
Definition:
Multi-axis (or dual-axis) charts use multiple axes to display different measures on the same chart, each with its own scale. This allows you to compare different types of data with distinct value ranges on a single visualization.
When to Use:
- Comparing Different Measures: When you want to compare measures with different units or scales, such as sales revenue (in dollars) and number of units sold.
- Visualizing Relationships: To observe the relationship between different measures over the same time period or categories.
How It Works:
- Create a chart by dragging one measure to the Rows or Columns shelf.
- Drag another measure to the opposite shelf to create a dual-axis chart.
- Each measure will have its own axis on the left and right sides of the chart.
Example:
- A line graph showing monthly revenue on one axis and a bar graph of units sold on another axis, sharing the same time dimension.
Visual Characteristics:
- Two or more y-axes (one for each measure) with different scales.
- Enables complex comparisons and insights across different data types.
Same-Axis
Definition:
Same-axis charts display multiple measures on a single axis, using the same scale for all measures. This approach is useful when comparing measures that have similar units or scales.
When to Use:
- Comparing Similar Measures: When you have measures that share the same unit or similar value ranges, such as different sales metrics (e.g., sales revenue and profit margin percentage).
- Simplifying Visualizations: To avoid the complexity of multiple axes and maintain a straightforward comparison.
How It Works:
- Create a chart by dragging multiple measures to the Rows or Columns shelf.
- Tableau will automatically place these measures on the same axis.
Example:
- A bar chart showing monthly revenue and profit margin percentages on the same axis.
Visual Characteristics:
- A single y-axis that represents all measures.
- Suitable for comparing metrics that are directly comparable.
Summary
- Multi-Axis: Uses separate axes for each measure, suitable for comparing data with different scales or units.
- Same-Axis: Uses a single axis for all measures, ideal for comparing metrics with similar units or scales.
Choosing between multi-axis and same-axis charts depends on the nature of your data and the insights you wish to convey.