How Many Arrows Are Too Many?
The Iceland Air route network.Objective:
Keywords:
An overloaded OD flow map (taken from Hennemann, 2013).Description:
Origin-Destination (OD) flow maps are popular for showing various kinds of movement data, such as airline travel networks or migrations of people or wildlife. Typically, an arc or arrow is used to illustrate either an idealized or actual travel trajectory, and sometimes this symbol is made thicker or thinner, or more or less saturated in hue, to indicate magnitudes of people or things moving. While these maps are intuitive, they suffer from over-cluttering relatively quickly, as only a few dozen or so arcs or arrows can make for so complex a network that it is difficult to follow with casual viewing.
While cartographers are well aware of this problem, there is little consensus on how to measure levels of clutter. This research will take a very user-centered approach, and attempt to determine acceptable levels of clutter by surveying human experiment participants for their opinions when shown maps of various levels of clutter. User ratings will be compared to objective, geometric measurements of map clutter (e.g., nodes or arcs per unit map area, fractical dimension, network degree, etc.).
References:
Jenny, Bernhard, Daniel M. Stephen, Ian Muehlenhaus, Brooke E. Marston, Ritesh Sharma, Eugene Zhang, and Helen Jenny. 2016. “Design Principles for Origin-Destination Flow Maps.” Cartography and Geographic Information Science 0(0):1–15. doi: 10.1080/15230406.2016.1262280.
Hennemann, Stefan. 2013. “Information-Rich Visualisation of Dense Geographical Networks.” Journal of Maps 9(1):68–75. doi: 10.1080/17445647.2012.753850.
Castner, Henry W., and Ronald J. Eastman. 1984. “Eye-Movement Parameters and Perceived Map Complexity—I.” The American Cartographer 11(2):107–17. doi: 10.1559/152304084783914768.
Domain(s):
Study Program(s):
- MSc. Cartography (EXCLUSIVELY externally advertised)
