for both types.

Origin-destination maps have a unique design focus on the schematic shape of the connecting lines. Straight lines are easy to draw, but can cause issues, especially when longer lines and shorter lines are collinear, obscuring each other and their destinations. They can also have a haphazard look. For these reasons, curved lines, typically circular arcs, are preferred as more aesthetically pleasing. They also have the ability to be adjusted to avoid intervening lines and points. Early automated line generation algorithms