Tableau is a powerful data visualization tool that offers numerous options to help users create insightful dashboards and reports. However, it can be frustrating when charts don't display data as expected. One issue that has puzzled Tableau users for years is the point at which stacked bar chart colors align with the legend. In this blog, we will discuss the problem, the reason for its occurrence, and potential solutions.
The Problem
When creating a stacked bar chart in Tableau and using a color-coded legend, the order of the stacked bars is sometimes opposite to the order in the legend. This issue can affect the readability of the chart, leading to confusion and incorrect interpretations.
For instance, let's say we have a dataset of five projects, A to E, with a corresponding amount and level. We want to create a stacked bar chart that shows the total amount for each project broken down by level. We have set level as a color-coded dimension on the chart, using the color mark. However, the colors of the bars may not match the order of the legend, resulting in a chart that is difficult to read and interpret correctly.
The Reason
The reason for this issue is that Tableau arranges the colors of the stacks based on the order in which the dimensions appear in the data shelf. By default, Tableau stacks the data in the reverse order from top to bottom.
For instance, if we have a dataset with two dimensions, A and B, and we stack them on the chart, the color of the stack for dimension A will appear at the bottom of the chart, followed by the stack for dimension B. Therefore, to achieve the desired color order, we should reorder the dimensions' location in the data shelf, with dimension A at the bottom and dimension B on top.
However, this solution may not be applicable for all scenarios. If, for instance, we want to stack the bars in alphabetical order, we must manually override the default order by creating a calculated field that forces the dimension to be sorted in alphabetical order.
Solutions
To fix the issue of colors being stacked opposite to the legend, there are several solutions to consider:
1. Reorder the Dimensions in the Data Shelf
One solution is to rearrange the order of dimensions in the data shelf. This method works best when dealing with relatively simple data that only requires sorting by dimensions or measures.
2. Create a Calculated Field
For more complex data, consider creating a calculated field that sorts the data according to the desired order. This approach requires using more advanced techniques, but it's the best solution when working with a large dataset.
3. Use a Custom Palette
Another solution is to use a custom color palette that matches the order of the legend. Creating a custom palette ensures that the colors match the order of the legend, although it may not be the best solution when dealing with patterns or colorblind users.
Conclusion
Tableau stacked bar chart color order being opposite to the legend can be a headache for many users. However, by understanding the root cause and various solutions, Tableau users can overcome the problem and create charts that accurately display data. In the end, using Tableau's numerous features and functionalities can lead to clearer, more informative dashboards and reports.