### CommonLounge Archive

April 18, 2018

In this tutorial, we are going to learn about Tableau, the popular visualization software used in analytics, media and business. It has powerful features and drag and drop functionality making it easier to interpret and present insights from data. You can learn more about the software and its different versions on the parent website here.

To create visualizations in this lesson, we will be using Tableau Public, the free version of Tableau software.

We will learn how to connect to a spreadsheet or file and create an interactive data visualizations for the web. Details on how to download and install Tableau can be found in this link.

# Getting Started

First open the folder where you saved the application on your computer and start Tableau Public (the steps for connecting to a file will be similar in Tableau Desktop). You should see the following home screen:

Note: If this is the first time you are using the application, you would not have any existing visualizations to work on. Hence, the central portion of the screen would be different, but the Connect and Discover panels on the left and right ends should be similar.

# Connecting to Data and Files

Let’s connect to the data and load our records for creating the visualization. As seen on the Connect panel, a wide variety of files are supported including: Excel sheets, JSON files, PDFs, Spatial files, and Statistical files. We also can connect to other file types using the “More” Option under ‘Server’.

Here, we will use the most common format — an Excel file — for our data mapping and chart creation. We will use the Sales dataset which can be downloaded from the following link.

Using the options on the Left Panel, connect to Excel data source. Select the file from the folder where the Sales superstore Dataset has been stored and click on ‘Open’.

Once the data is connected, a blank workbook will open up automatically as follows.

As seen on the Sheets tab on the left, all excel worksheet tabs have been connected. You will notice that the central area of the workbook is blank and states “Drag Sheets here”. Drag “Orders” from the “Sheets” tab to this central area. Depending on the size of the data, it might take a couple of seconds for the data to be loaded. The Tableau workbook should now look similar to screenshot below.

Next:

1. Click on the “Go to Worksheet” button on the bottom left (in the above image)
2. Select “Sheet1”
3. A blank visualization sheet will open up — we will use this to start creating visualizations.

Observe how the left panel is populated with all the parameters or columns from our Excel sheet. They are also categorized as Dimensions and Measures. Put simply, Measures are numerical values like Profits that we can perform arithmetic operations on, such as sum, average, etc. Dimensions are categorical values that provide additional information or classification such as OrderId or Product Name.

Note: Tableau does allow conversion of Measures to Dimensions and vice versa. For instance, Sex/Gender might be encoded as 0 or 1. While numerical, it will populate as a Measure but is in fact a Dimension. Put another way, arithmetic operations like average or variance do not hold true for this variable.

Tip: Hover on Dimensions, you will notice font is Blue. Measures values are displayed in green font on Tableau.

# Create the Visualization: Bubble Charts

Now we are ready to start the visualizing our data. We will explore bubble charts in this lesson as we explore the tool and understand its various powerful features.

Before we begin, a short note on why we are choosing bubble charts for our visualization. Also known as packed bubbles view, it is a cluster of bubbles packed tightly to display a large variety of fields. Used in conjunction with the Size and Color card from Marks card, they can visually display relative values for the Dimensions or Measures under consideration. While the arrangement of bubbles is tool driven, the combination of color, size and fields make up for a simple visual that can illustrate multiple fields and relative significance.

In this visualization, we want to view Profits made in different category and sub-categories. As we are inspecting how profitable or not different categories were, we will be using the Bubbles chart.

Let’s get started.

First, select Category from the Dimensions. Drag over to the field labeled Rows on the top of the sheet. The different values will populate as follows:

Now:

1. Take Sub-Category from Dimensions (left menu) and drag it over to Rows
2. Take Profit from Measures (left menu) and drag it to Columns.

Tableau will automatically render a bar graph on completing these steps.

Click on the down arrow next to SUM(Profit) on the Columns category. It will show you a list of measures and aggregations that you can use.

Here, we shall retain the sum aggregations, but feel free to explore the different statistic options available.

Next, on the top right of the sheet is a button that says ‘Show Me’. Clicking on it will open up different types of charts available. Hover on “Bubble chart”. It will denote what kinds of parameters are necessary to make such a chart. Go ahead and select it.

Notice how the visualization changed in appearance and color. New values were automatically re-assigned from Rows and Columns to the Marks Panel on the left of the visualization.

As seen here, Tableau automatically assigned color to Category values. We can change them as per business requirements. Simply double click on the color icon in Marks panel.

Click on “Edit Colors”. Since default values are automatically applied, choose colors from those displayed or select more from the dropdown. Here, we can simply select the value, select the color and then assign it. Repeat the process for all values.

Once applied, your visualization or viz (as is popularly called by Tableau users) will get altered to reflect the changes, including the legend on the right column.

You may be wondering why the bubbles are of different sizes. Upon close inspection, it can be seen that Profit metric has been applied to Size card on the Marks panel. This is the reason why the bubbles in the are not uniform in size — their size is proportional to the corresponding profit. We can change the size of the bubbles depending on the value assigned to the Size card.

We can also add filters to increase interactivity. Here, we can add a simple date filter. Drag the Ship Date (from the Dimensions panel) field to Filters panel. The action will open up a pop-up as follows.

Use Range of Dates and select Next. Keep the dates in range of 1/1/2011 and 12/31/2015 and apply. You will notice that the viz did not change significantly but the Ship Date is now successfully in the Filters card. Right click on the Down arrow next to this value. Select Show Filter option and view how the filter now appears in the right hand corner of the viz.

Slide the date filter to observe how the profits change over the time periods for the different categories.

Now that our viz is ready, rename the worksheet as Profit-Categories. Renaming the sheet will also change the title of the viz.

Now that the viz is completed, save the file. For Tableau Public users, you will be directed to your Online Tableau Public profile as follows:

Enter your credentials and follow the prompt to save your file. Congratulations, you just made your first Tableau visualization and can now use the tools to make more.