Visualizing More Than 2 Attributes

Stacked and Grouped Bar Charts

Stacked Bar Charts

If we have two attributes, with x and y values respectively, we will have x bars, each with y stacked components.

This is particularly useful when we need to visualize proportions.

Grouped Bar Charts

If we have 2 attributes, with x and y values respectively, we will have x groups with y bars per group.

This is particularly useful when we want to compare every single value to another.

Line Charts and Stacked Area Charts

Line Charts

Say we have a line chart with the number of collisions plotted over a given time range.

To represent a 3rd attribute, say 'borough', we can use one of two line chart visualizations: a single line chart with one line per borough, or multiple line charts, one per borough. The former is useful if we need to compare the boroughs, since all the lines are on a single chart.

Stacked Area Charts

These are particularly useful if we need to compare the proportions of quantities and how they change with time.

However, it isn't effective if we need to read the values or compare the values over time. This is because, since the lines are stacked, their pattern depends on that of the one below them, thereby not denoting actual values.