This graph shows the flow of embedded carbon emissions between Australian and Chinese cities. Despite the large number of cities, and a web of lines, this graph is remarkably clear, likely due to the way the cities are ordered. In this case it is also likely a good choice not to use color.
From the paper:
Inter-regional, per-capita flows of embodied carbon emissions instigated by city final demand, (the largest bilateral flows are labelled).
Please note that these data visualizations come from external sources (journal publications, academic books, reports, etc.). Copyright of these data visualizations is held by the publishers or authors. We have included these data visualizations on our website under the principles of fair use. However, if you would like to reuse any of these images be sure to either comply with the rules around fair use in your country or consult the original authors or publishers if in doubt.