I'm designing / implementing an animated visualisation of flow of people between departments in a building.
Departments are presented as circular nodes, where the size of the node indicates volume at a given time. Connections between nodes need to indicate volume of flow between departments.
I'm struggling to decide how to present the flow of people, given that the graph has many overlapping paths, and this could cause the visualisation to quickly become too busy or unclear.
My graph has at least 5 nodes, and people can flow from any node to any other. There are also entry and exit nodes I've excluded for simplicity.
Line width is one option to indicate volume of flow, although direction of flow may be difficult to represent.
I also thought about using small coloured circles moving along the paths (as in the example at the top of this page), but I feel that might get too cluttered with so many paths overlapping.
In short, I'm looking for a clear way to present directional flow in a graph with multiple overlapping paths. Any suggestions appreciated. Thanks!