Design principles for origin-destination flow maps
▻http://cartography.oregonstate.edu/pdf/2017_Jenny_etal_DesignPrinciplesForODFlowMaps.pdf
ABSTRACT
Origin-destination flow maps are often difficult to read due to overlapping flows. Cartographers
have developed design principles in manual cartography for origin-destination flow maps to
reduce overlaps and increase readability. These design principles are identified and documented
using a quantitative content analysis of 97 geographic origin-destination flow maps without
branching or merging flows. The effectiveness of selected design principles is verified in a user
study with 215 participants. Findings show that (a) curved flows are more effective than straight
flows, (b) arrows indicate direction more effectively than tapered line widths, and (c) flows
between nodes are more effective than flows between areas. These findings, combined with
results from user studies in graph drawing, conclude that effective and efficient origin-destination
flow maps should be designed according to the following design principles: overlaps between
flows are minimized; symmetric flows are preferred to asymmetric flows; longer flows are curved
more than shorter or peripheral flows; acute angles between crossing flows are avoided; sharp
bends in flow lines are avoided; flows do not pass under unconnected nodes; flows are radially
distributed around nodes; flow direction is indicated with arrowheads; and flow width is scaled
with represented quantity
#cartographie #ligne #flux #circulation #sémiologie #sémiologie_graphique #sémantique
