So, these visual properties are actually the visual channels,
what we call visual channels.
So, visual channels are graphical properties that
one can use to represent information visually.
It turns out that there are many other possible visual properties,
graphical properties that one can use in visualization to represent information.
In the previous examples,
I mentioned position and length of a bar,
but there are many many other visual properties that one can use.
Here is a summary table of some of the most popular properties that one can use.
I've taken this table from the PhD thesis of Eamonn Maguire,
who actually created a lot of
really interesting and nice visuals to show how visualization works,
and this is a summary table, as I said,
that represents all the main visual properties that one can use.
So, I want to walk you through some of them.
For instance, we have size.
One can use size to represent quantity.
The bigger something is the more quantity it represents.
One can use color intensity.
So, the brighter something is and the higher the value it represents, or say,
the slope of a line can represent a quantity, or different color,
what we call color hues,
which is basically the name of the colors,
can represent different categories, and so on.
So, there are many different visual channels and the main idea is that visual channels
can be used to represent information that is contained in the data.
Before I conclude, I want to give you another practical example.
So, here is another graph taken from the famous Gapminder tool created
by Hans Rosling to basically represent
the temporal evolution of human conditions around the world.
This specific graph is a scatter plot and it basically
represents the relationship between income in different countries and life expectancy.
Every single bubble here represents one country and the color represents
different regions in the world and size of the bubble represents the population size.
So, here, if you think about it,
we have many different channels used at once.
So, the symbols are the bubbles and each bubble,
as I said, represents one country.
But, now we have associated these bubbles a number of different visual properties.
So, what are these properties?
There is the X position of the bubble,
there is the Y position of the bubble.
These are already two visual channels,
X position and Y position,
then we have the size of the bubble.
This is yet another channel that represents population size,
and then we have color that represents different regions in the world.
So, once again, these are examples of visual channels.
