How to Size Aesthetic
The size is often used aesthetic parameter in statistical graphics.
As with other parameters, the size property can be set or mapped.
If you want to set this property, use numerical value. If you use
point geometry, the size values ranging mostly from 1 to 10. For
text geometries (geom_text), you can use larger values. Quickly
you can set this property using features hidden in the context-menu.
Examples of different point sizes are shown in the following figure.
As you can see, if you change the size property, this property is
also reflected in legend. The size of points in legend you can change
using the function guide.
If you map the size to variable from the dataset, you can use
continual or categorical values. The following figure, in addition
to size mapping, displays one more important feature. If you define
the same mapping for several aesthetic properties (e.g. point color
and shape), individual legends for aesthetics will be merged.
Size parameter can be defined for several types of geometry layers.
Multiple geometries support the size aesthetic, such as geom_line or
geom_path. Example of its use in geom_path layer is shown in the
following figure.