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.

Not sure what I'm missing. If I click on Madagascar in the left box, the map zooms into Madagascar, but all the other arcs are still visible and not filtered out.

You can use the search button (left panel top) to filter arcs by place/collection. The left panel functions more like map navigation, while the search/command palette is a separate mode.