Enumerates basin-level summaries for minima or maxima in a gfc.flow
result. Basin sizes are taken from gfc.flow$summary /
gfc.flow$summary.all. The number of incident cells is computed from
list.cells().
Enumerates basin-level summaries for minima or maxima in a gfc.flow
result. Basin sizes are taken from gfc.flow$summary /
gfc.flow$summary.all. The number of incident cells is computed from
list.cells().