  We present route packing, a novel (geo)visualization technique for displaying
several routes simultaneously on a geographic map while preserving the
geospatial layout, identity, directionality, and volume of individual routes.
The technique collects variable-width route lines side by side while minimizing
crossings, encodes them with categorical colors, and decorates them with glyphs
to show their directions. Furthermore, nodes representing sources and sinks use
glyphs to indicate whether routes stop at the node or merely pass through it.
We conducted a crowd-sourced user study investigating route tracing performance
with road networks visualized using our route packing technique. Our findings
highlight the visual parameters under which the technique yields optimal
performance.
