Design principles for origin-destination flow maps

Using Eye Tracking to Evaluate the Usability of Flow Maps

“…Although the participants performed less efficiently while reading the curve maps, curve maps contribute to a more effective performance than straight-line maps, which is similar to the findings of previous studies [1]. This finding is mainly reflected in the results of accuracy, as the curve group exhibited a greater number of correct answers than the straight-line group (Table 3 and Figure 3).…”

“…They discovered that users performed better with straight lines, although they preferred curved graphs. However, Jenny et al [1] found that curved flows are more effective than straight flows, arrows indicate direction more effectively than tapered line thicknesses, and flows between nodes are more effective than flows between areas. Furthermore, through a literature review, experimental data analysis, and questionnaire survey methods, they derived several design principles about flow maps, including reducing curve overlap, avoiding excessive curvature, and avoiding curves of unconnected nodes.…”

“…Each group had four maps using straight lines and four maps using curves. Normally, point size represents quantized attributes of locations in flow maps [1,26,27,30]. In material maps, point features that represent cities do not have the same size because the size variable is used to represent the total volume of flow in each city.…”

“…Flow maps are effective tools to represent connections and interactions volume between geographical regions [1], and are widely applied to research related to spatial trajectory and interactions, such as migration [2], transportation [3], population movement [4], disease spread [5], and social communication flows [6]. Researchers use various methods to generate flow, such as force-directed edges [6,7], bundled edges [8], and 3D curves [9].…”

HazMatMapper: an online and interactive geographic visualization tool for exploring transnational flows of hazardous waste and environmental justice

“…HazMatMapper includes four primary interface components: (a) a central map, depicting sites as proportional symbols scaled by imported hazardous waste with trade connections depicted as flow lines, or states as color-shaded choropleth maps (Dent, 1999;Slocum, McMaster, Kessler, & Howard, 2009). We use curved lines to depict shipments of waste between hazardous waste importers and exporters, following recommendations from Jenny et al (2016); (b) configuration controls, allowing users to re-express the dataset by site level or state level, and toggle between solid or liquid waste (each potentially measured as kilograms or liters); users also can search for specific wastes; (c) advanced context controls providing a stacked histogram overview of the dataset by percentage, overlays related to EJ concerns, and temporal filtering controls; and (d) an information panel providing details about a geographic feature selected in the map (see Figure 1). Following Shneiderman (1998), HazMatMapper users first configure an overview map at the site level or state level, zoom and filter the map to explore patterns across space and scale, and then retrieve details about specific geographic features and attributes deemed interesting through interactive exploration, ultimately downloading the original manifest PDF scans to relate unique records to potential EJ concerns.…”