link's segments for one species in a set of groups, with flow and access, for grading

The segment table a grade is written on: every streams row of the groups, with streams_access.access_<sp>, the species' habitat flags (re-gated on access, stored flags beside), and wet's picked annual flow. Own flow is one join; the parent fallback knw_link_flow() applies per visit (the nearest primary-flow segment on the main line or the segment's own line) runs only on the segments with no own flow, so millions of segments read in one pass.

Usage

knw_link_segments(conn, schema, species, wsg, parent_fallback = TRUE)

Arguments

conn: a DBI connection to a database holding schema and discharge.
schema: character(1) link persist schema.
species: character(1) species code.
wsg: character watershed group codes.
parent_fallback: logical(1) run the parent fallback for segments with no own picked flow.

Value

A tibble, one row per segment: id_segment, watershed_group_code, linear_feature_id, blue_line_key, downstream_route_measure, upstream_route_measure, length_metre, edge_type, stream_order, waterbody_key, gradient, channel_width, channel_width_source, wscode, localcode, access, accessible, spawning, rearing, lake_rearing, wetland_rearing (re-gated), *_stored, mad_pick, pick_source, flow_from.

Examples

if (FALSE) { # \dontrun{
conn <- DBI::dbConnect(RPostgres::Postgres(), bigint = "numeric")
seg <- knw_link_segments(conn, "fresh_default", "CH", c("BULK", "MORR"))
} # }