A length in one dimension, starting at a common baseline; as in a bar chart.
scaleX is in scope, the bar will be oriented horizontally; vertically if
scaleY is in scope.
scaleY must be in scope, but not both.
The dimension of the data which sets the width or height of the bar.
Bar charts are a familiar friend, mapping a single quantitative measure to the length of bars that share a common baseline. Since people read the value of a bar from its length, an honest bar chart must always start at 0. If the variation between data is too small to see on a bar chart that starts at zero, consider using a dotplot instead.
While most bar charts are oriented vertically, they work just as well when oriented horizontally. In left-to-right and right-to-left reading languages, orienting the bars horizontally will both provide more room for labels and make them more readable.