How a chart's own proportions are treated when it is mapped onto the pins.
stretch spends every pin, which is what most charts want: a bar chart's
shape carries nothing, and letterboxing it would throw away rows a fingertip
could have used to tell two bar heights apart.
preserve keeps the chart's aspect ratio at the cost of leaving pins unused.
A pie, a radar, a chord diagram and a map are read by their shape, and
stretching one does not blur it — it misreports it. A circle arriving as a
1.5:1 ellipse makes a wedge at the top subtend a different arc from the same
wedge at the side, so the reader concludes one slice is bigger than the
other when the data says they are equal.
How a chart's own proportions are treated when it is mapped onto the pins.
stretchspends every pin, which is what most charts want: a bar chart's shape carries nothing, and letterboxing it would throw away rows a fingertip could have used to tell two bar heights apart.preservekeeps the chart's aspect ratio at the cost of leaving pins unused. A pie, a radar, a chord diagram and a map are read by their shape, and stretching one does not blur it — it misreports it. A circle arriving as a 1.5:1 ellipse makes a wedge at the top subtend a different arc from the same wedge at the side, so the reader concludes one slice is bigger than the other when the data says they are equal.