In this lesson, we focus on one of
the most important channels we have available in visualization, which is color.
Color is an extremely powerful channel,
and it is ubiquitous in visualization,
you can find the use of color in so many different situations and projects.
So, what is it used for?
There are many purposes for color,
but here I want to focus on three main ones.
So the first one is to detect patterns in the data.
The second one is to label data so that we can distinguish between different categories,
and the last one is to highlight specific objects or instances so that you
can drive the attention of people into some specific regions or objects.
Let me give you examples of each of these purposes.
So, the first one is encoding quantities
with color so that we can see some patterns in the data.
An example is this map.
In this map of South America,
color is used to visualize information about altitude.
So this is an example of using color to encode information about a quantity,
and by doing that,
we can see a pattern, actually,
a geographical or spatial pattern through this specific kind of encoding.
This next one is somewhat similar but also different because it is not geographical.
Here I have a table,
and the frequency of
the elements in each cell of this table is encoded with the intensity of the color.
Again, this is a way to visualize a quantity
through color and to actually make sure that there are
some patterns that stand out and
hopefully guide you towards interesting pieces of information.
The next one is to use color to label
data so that we can distinguish between different sets of categories.
An example is this scatter plot.
In a scatter plot,
you can encode information by position but also by giving different color codes to
different items so that you can see how they
distribute in the space that is generated by these two axes.
So, when color is used in this way,
it is very useful means to basically figure
out where objects of a certain type are located.
The final one is to highlight visual elements in a visualization.
Here, I have a number of line charts,
and in each one,
I want to highlight one single line so
that you can see this single line in comparison to all the others.
So, in this case, as you can see,
there is a background that is gray and
the line that is highlighted in red so that it stands out.
Okay. So these three main uses,
these three main purposes;
to encode quantities, to visualize patterns,
encode categories and label data so that you can
recognize where objects of a certain type are,
and finally, use color to make some objects standout compared to the rest.
Enrico BertiniAssociate Professor
Cristian FelixPhD. Candidate
