Interactivity in Tableau (continued)

This week we will take a look at sets and groups feature in Tableau. Let’s start with sets –

Sets are user defined fields which help in viewing a subset of the entire data. We can create sets on dimensions using conditions or specific data points. It is interesting to note that whenever the underlying data changes, sets are recomputed based on whether they are constant sets or compute sets. Seems quite similar to filters, isn’t it? Yes, a lot of the functionality is same, such as dynamically obtaining a subset of the data and the ability to be applied across the workbook. However, the differentiating point is that sets can be used in other calculated fields. This is particularly useful, when creating a subset of the data, using a set or filter, is just the starting point of your analysis. Let’s take a look at how we can create sets:

  • Constant sets: This option is similar to that of the Keep Only/Exclude option while creating filters. Using this option, the user can select the data points which he/she is interested in and then keep those only in the visualization for further analysis. The important point here is that once created, the data points in the set do not change dynamically. This can be achieved by selecting the data points in the visualization and selecting the Create Set option in the Tableau prompt. There is also an option to perform a negation operator by selecting the “Exclude” option in the following prompt. For our speed violation data set, if we have a map of violations in the map for Chicago with the addresses marked as per violations reported, the user can create sets based on areas of interest or select the top three violations and just focus on those.
  • Compute sets: Using this option, the user can create sets which dynamically change when the underlying data changes. To create such a set the user can select a dimension and select the create option. There are three options to create sets – general, condition, and top. The general tab allows the user to view the entire list of data and choose from it. The condition tab allows the user to create a condition based on which the set will create the subset of the data. The third tab, known as “Top”, is probably the most used for numerical analysis. This tab has options for the user to perform Top N or Bottom N analysis. For our example data set, we can use a set to create a Top N analysis of addresses with the highest number of violations. This can be extended further by making the “N” value as a parameter, allowing the user to specify how many addresses he/she wishes to see in the “Top List”.

As a final point on sets, it is important to mention the IN/OUT option which helps the user switch between the subset and the rest of the data.

Groups are similar to a set and help to organize the data better in a visualization. They help to create hierarchy within dimensions, thereby helping the user organize the data items within a dimension. We can create a group by manually selecting the data items in the visualization and then choosing the Group icon which comes up in the Tableau prompt. This way the group that is created gets automatically added to the shelf/card. You can also create groups by selecting a dimension and performing right-click and then create option. If the list of members is huge, like similar to our data set containing a huge list of addresses, the create group option also gives us a “Find” option using which we can do a search on the dimension members. For e.g. if we want to create a group for addresses with the name “N WESTERN” in it, then just search using this string and the members get highlighted from the entire list. Another interesting use case for groups is to use it for data standardization. We may have encountered data sets which contain the same data member spelt in various ways, such as “Santa Clara University”, “SCU”, “Santa Clara Univ.”, etc. This kind of data set will create problems when we want to aggregate measures for Santa Clara University. This problem can be solved by grouping the above mentioned items into a single group since they represent a single entity.

We will take a look at actions in the upcoming blog!

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