Using the preceding bar chart, you can easily see that the technology department has more total sales than either the furniture or office supplies departments. What if you want to further understand sales amounts for departments across various regions? Follow these two steps:

1. Navigate to the Bar Chart (two levels) sheet, where you will find an initial view identical to the one you created earlier
2. Drag the Region field from Dimensions in the data pane to the Rows shelf and drop it to the left of the Department field already in view

You should now have a view that looks like this:

You still have a horizontal bar chart, but now you've introduced Region as another dimension that changes the level of detail in the view and further slices the aggregate of the sum of sales. By placing Region before Department, you are able to easily compare the sales of each department within a given region.

Now you are starting to make some discoveries. For example: the Technology department has the most sales in every region, except in the East, where Furniture had higher sales. Office Supplies never has the highest sales in any region.

Let's take a look at a different view, using the same fields arranged differently:

1. Navigate to the Bar Chart (stacked) sheet, where you will find a view identical to the original bar chart.
2. Drag the Region field from the Rows shelf and drop it on to the Color shelf:

Instead of a side-by-side bar chart, you now have a stacked bar chart. Each segment of the bar is color-coded by the Region field. Additionally, a color legend has been added to the workspace. You haven't changed the level of detail in the view, so sales are still summed for every combination of region and department:

• • If Department is the only field used as a dimension, you will have a view at the department level of detail, and all measures in the view will be aggregated per department.
  • If Region is the only field used as a dimension, you will have a view at the region level of detail, and all measures in the view will be aggregated per region.
  • If you use both Department and Region as dimensions in the view, you will have a view at the level of department and region. All measures will be aggregated per unique combination of department and region, and there will be one mark for each combination of department and region.

Stacked bars can be useful when you want to understand part-to-whole relationships. It is now fairly easy to see what portion of the total sales of each department is made in each region. However, it is very difficult to compare sales for most of the regions across departments. For example, can you easily tell which department had the highest sales in the East region? It is difficult because, with the exception of West, every segment of the bar has a different starting place.

Now take some time to experiment with the bar chart to see what variations you can create:

3. Navigate to the Bar Chart (experimentation) sheet.
4. Try dragging the Region field from Color to the other various shelves on the Marks card, such as Size, Label, and Detail. Observe that in each case the bars remain stacked but are redrawn based on the visual encoding defined by the Region field.

5. Use the Swap button on the Toolbar to swap fields on Rows and Columns. This allows you to very easily change from a horizontal bar chart to a vertical bar chart (and vice versa):

6. Drag and drop Sales from the Measures section of the data pane on top of the Region field on the Marks card to replace it. Drag the Sales field to Color if necessary, and notice how the color legend is a gradient for the continuous field.
7. Experiment further by dragging and dropping other fields onto various shelves. Note the behavior of Tableau for each action you take.
8. From the File menu, select Save.