7
assignments
Beginner
Skill Level
30 min
duration
Introduction
Tableau Desktop offers a wide range of possible visualizations, including bar graphs, line graphs, pie charts, maps and many others. In this third lesson of our free training, you'll learn how to create and customize these basic visualizations to present your data in the most effective way.
In this lesson you will learn
- How to create basic visualizations in Tableau
- How to modify created visualizations
- How to customize colors of your dashboard yourself
Why should you visualize data?
Why visualize data in the first place? We visualize data because we as humans are much better at recognizing patterns visually than we are at drawing conclusions from a table full of numbers. Watch a BBC video of 5 visualizations that have changed the world below, and find out why visualizing is very valuable.
Creating visualizations
It is very simple to create a visualization in Tableau Desktop. You select the data you want to use in data pane on the left side of your screen. Then you drag the fields to the 'Rows', 'Columns' and 'Marks' ' cards to build the visualization. You can also use the 'Show me' to quickly and easily create a visualization based on a predefined template. We recommend that you become familiar with Tableau yourself without using show me. The assignments in this training will help you do that.
Tableau works with so-called sheets. On these sheets you create a visualization (for example, a bar chart or a line chart). Each visualization gets its own sheet. Then you combine these sheets together to create a dashboard. In Chapter 8 we will learn how to create a dashboard. But so the first step is to create a sheet of your dashboard. What kind of visualization you make depends on the type data you are working with and what question you are trying to answer. In this training we won't go into detail about when it's best to use which visualization. If you are interested in that anyway, this dashboard by colleague Andy Kriebel is a good starting point. First, let's start by creating a bar chart.
Bar chart
We start by creating a standard bar chart. Click on Sheet 1 if you haven't already opened it.
- Drag the 'Product'field from the data pane to the Columns shelf.
- Then drag and drop "Sales" to the Rows shelf.
Voilà, there is your very first visualization. Life can be that easy. Here you can also see the discrete and continuous fields in action. In the background, Tableau looks at what products there are, and groups them. Next, we add the Sales. Tableau then adds up all the Sales by Product, and displays them as a bar chart. Tableau then adds up all Sales by Product, and displays them as a bar chart. The choice of chart type Tableau does automatically and is based on visual best practices belonging to this combination of data types. A helpful tip is to save your work and not just click away, because in this training we will build on the assignments we create in the same workbook.
It's good to look back at your visualization. It seems very intuitive, three columns for three product categories along with the total value of sales. And if you look closely at the little green pill, you'll see what you actually knew as knew: Tableau added up all the values stored per line in the original table, then broke them down by product category. Tableau will always go for an aggregation (= grouping/merging) for continuous (green) metrics. By default this is a sum, but you can choose another form of aggregation yourself.
Right click on the little green pill with SUM(Sales), halfway down the menu you will now see Measure (Sum) . If you hover above with your mouse, you will see that in addition to the sum, you can choose other aggregation levels, such as mean, median, maximum and minimum. You can choose from all these (statistical) aggregation forms because Tableau will always want to summarize all the values in the whole column into one number. It is important to understand this if you want to perform more complex calculations later.
Line chart
We got the hang of it and went right ahead with making a Line Chart.
- Creates a new sheet.
At the bottom of the screen, next to Sheet 1 are three smaller buttons. The first button creates a "New worksheet. You can rename sheets by double-clicking on them and entering the new name.
Now that we have a new blank worksheet we are going to start working on the Line Chart.
- First drag the column Order Date to columns.
- Drag Next Sales to Rows.
We now have a simple line chart by year. We are going to modify this to a line chart for each month.
Click in the columns shelf with your right mouse button on YEAR(Order Date), and select the option Month May 2015.
Pie Chart
Another visualization you often see is a Pie Chart or pie chart. This circle is divided in pie points and indicate a division between different categories. To create a Pie Chart we will first open another new sheet.
- If you hadn't already done so: rename the sheet from the previous exercise to 'Line Chart'.
- Create a new sheet Create.
- Click on the drop down menu in the Marks Card, where it now says Automatic.
- Choose the Pie option . Tableau thus knows that we want to create a pie chart. So we see that an additional option appears in the marks pane, which is 'Angle'. We want to see in our Pie chart the Profit (profit) per store segment.
- Add the Segment column by dragging it onto Color in the Marks Pane. The circle is now divided into the number of categories in the dataset, three in this case.
- Drag the Profit to Angle in the Marks Pane. This divides the 360 degrees of the circle (the total profit) among the three categories based on their relationship to each other.
For example, we created a pie chart.
Customizing visualizations
Once created, you can modify a visualization customize by adjusting the colors, fonts, labels, axes and other properties. You can also filters and parameters added to make the visualization interactive, allowing users to zoom in on specific parts of the data. In training 5 on Filters and Sets, we go into this in more detail.
For now, we are going to colors add colors to our charts. Let's start with the bar chart. We would like to color the bars by how many sales they have. So the darker, the more sales.
- At the bottom of your screen, go back to the sheet 'Bar Chart'.
- We want to color Sales, so pick up Sales and drag to Color in the Marks Pane.
Tableau colors the Bar Chart then automatically based on which bar has the most/least sales. A legend automatically appears on the right side of the screen showing which color means what. Since we add color based on a continuous value on one scale (money), we also see a continuous gradation of one base color.
- In Tableau Desktop, return to the Bar Chart sheet.
- Right-click in the Legend and choose 'Edit Colors'. You can now apply a different color. You can also do this by clicking on Colour in the Marks Pane.
COLOR USE: DIMENSIONS VS. MEASUREMENTS
Besides based on continuous values, we can of course assign colors to different categorical values, as we already saw with the Pie Chart. We can adjust those colors there too, if we want to. This works in exactly the same way. Also in the Line Chart You could drag a dimension/categorical field to color. This adds an additional layer of information, and breaks up the one line you saw into the number of different values the field used - each with a different color.
If you now go back to the Pie Chart, where Segment is already set to Color, you will see that your pie chart has the same colors as the same segments at the Line Chart. If you adjust these colors at the Pie Chart, you will see that they are also adjusted at the Line Chart. So, since the values in the Segment field are discrete, we also use different (ground) colors for different values here. Don't forget to save your work because we will continue with the visualizations created.
Note: If you use colors to distinguish, for example, different product categories, you associate those colors with specific values. If you then use the same colors again on the same dashboard for other values, you create associations between values in your dashboard that you don't mean at all. More on this in Chapter 10, Best Practices.
Conclusion
In this section, you learned how to create and customize some basic visualizations in Tableau Desktop. By using the different visualization types and customizingproperties such as color, you can present data effectively and provideinsight into the trends and patterns hidden in the data. In the next chapter, we will create our own calculations that we can use in our visualizations.