FWA_Upstream pairs for the irregularly coded polygons of one basin

A polygon whose localcode neither equals nor lies under its wscode is irregular: FWA_Upstream's localcode guards treat it differently from the range structure wet_upstream_sums() relies on. This returns, for each such polygon b, every watershed a that FWA_Upstream(a, b) counts it upstream of (including itself). The join is small: a.wscode_ltree @> b.wscode_ltree restricts candidates to the few streams whose code is a prefix of b's, via the gist index.

Usage

wet_upstream_irregular(conn, wscode)

Arguments

conn

A DBI connection to an fwapg database.

wscode

Character. FWA watershed code of the basin root.

Value

data.frame(watershed_feature_id, id_up).