Description

The subunits layer for the USA map includes slivers of Canadian provinces (which is unintended).

Screenshots

Steps to reproduce

• Open /dist/topojson/usa_50m.json in Mapshaper
• Zoom in to the top of Washington state
• Note the sliver of British Columbia above Washington

Notes

• This issue stems from the fact that the world subunits layer (coming from NE data) is clipped using the shape of the USA from the UN
• These two shapes don't match exactly, so the slivers result from the clipping operation
• We should check the other subunits layers for a similar issue