Scales: automatic scaleSource:
Scales in tmap are configured by the family of functions with prefix
Such function should be used for the input of the
.scale arguments in the
layer functions (e.g.
tm_polygons()). The function
is a scale that is set automatically given by the data type (factor, numeric, and integer)
and the visual variable. The tmap option
scales.var contains information
which scale is applied when.