bou_southsea.RdAn sf object with the "十段线" (ten-segment line) national boundary in the
South China Sea region, used as the default content of geom_submap().
bou_southseaAn sf object with a single MULTILINESTRING feature (WGS 84),
covering roughly 108-123°E and 3-25°N.
ChinaBound2024, bou1_4l_十段线.shp.