Thanks! You actually can filter by source already, search lets you filter arcs by place/site. Destination filtering technically works too, via Collections, but that only makes sense while there are a handful, once it’s hundreds it’ll need its own proper destination filter. Good call on the color/gradient distinction for source vs. destination on the arcs too, that’s worth trying.

One thing I'd find interesting is the inverse view: instead of starting from a place or artifact, start from a museum and visualize the geographic footprint of its collection. It could make the collection's provenance surprisingly tangible, especially for institutions with very global holdings.