Conceiving and Reasoning Visualization Design Options - Data Visualization: A Successful Design Process - page 103

Here is a brief outline of the variety of types of functions and features you should
consider building into your interactive work:
Manipulating variables and parameters
The complexity of some data frameworks often means we are trying to find ways of
showing many dimensions of stories within a single display or to facilitate different
combinations of variables for exploratory visual analysis. The ability to select, filter,
exclude, or modify certain variables is a valuable way of letting the user interact with
different slices of the data. Furthermore, grouping and sorting options are common
facilities for extracting new insights.
In the Sankey diagram example, you can isolate any of the vertical segments to see
the breakdown and flow of those individual components across the entire system.
You can also modify the variable of time using the slider to see changes across
numerous yearly milestones.
A technique called "brushing"—highlighting a set of data marks—is another
powerful way of focusing in on a subset view of our presented data, particularly
with scatter plot type displays.
Adjusting the view
In contrast to manipulating variables, this is more about adjusting the user's lens
or window into the subject. When we have hierarchical or high-resolution data, the
ability to perform vertical exploration through the different layers of detail is an
important feature. This can be particularly valuable in map-based visualizations
where you may wish to pan around the landscape and zoom through different levels
of magnification. You would see the benefit of this in a project such as the "Wind
Map" that we saw earlier, enabling the user to dive into different parts of the country
or those areas with strong winds that would be interesting to see in more detail.
An additional element of view adjustment is to create different horizontal tabs or
panels of data. For example, if you wanted to show your data stories via a series
of explanatory sequences. Collapsible devices such as concertinas allow for extra
detail to be neatly organized hidden away from the default view and revealed when
required. In the energy flow example, we also see a full-screen option that enables
users to optimize the screen space occupied by the interactive.
Annotated details
We'll learn more about annotation shortly but, in interactive terms, this is about
creating extra layers of data detail through interactive events such as hovering or
clicking. This is particularly useful if you want to reveal actual data values or extra
detail about a given category or event.