Validate Breaks Against Upstream Evidence

Filter break points by checking for upstream evidence. For each break, counts rows in evidence_table that are upstream on the same blue_line_key. Breaks with count >= count_threshold are removed.

Usage

frs_break_validate(
  conn,
  breaks,
  evidence_table,
  where = NULL,
  count_threshold = 1L
)

Arguments

conn

A DBI::DBIConnection object (from frs_db_conn()).

breaks

Character. Table name containing break points with blue_line_key and downstream_route_measure columns.

evidence_table

Character. Schema-qualified table with evidence features. Must have blue_line_key and downstream_route_measure columns.

where

Character or NULL. SQL predicate to filter the evidence table (without leading AND/WHERE). Column references use alias e. Examples: "e.species_code IN ('CO','CH')", "e.observation_date >= '1990-01-01'".

count_threshold

Integer. Minimum upstream evidence count to remove a break. Default 1 (any evidence removes the break).

Value

conn invisibly, for pipe chaining.

Details

This is generic — the evidence table can contain any point features with blue_line_key and downstream_route_measure columns (fish observations, water quality stations, SAR sightings, etc.). Use where to filter the evidence to relevant records.

See also

Other habitat: frs_break(), frs_break_apply(), frs_break_find(), frs_extract()

Examples

if (FALSE) { # \dontrun{
conn <- frs_db_conn()

# Remove gradient breaks where coho or chinook were observed upstream
conn |>
  frs_break_validate("working.breaks",
    evidence_table = "bcfishobs.fiss_fish_obsrvtn_events_vw",
    where = "e.species_code IN ('CO', 'CH')")

# Remove breaks with 5+ recent observations of any species upstream
conn |>
  frs_break_validate("working.breaks",
    evidence_table = "bcfishobs.fiss_fish_obsrvtn_events_vw",
    where = "e.observation_date >= '1990-01-01'",
    count_threshold = 5)

# Generic: validate against any point evidence table
conn |>
  frs_break_validate("working.breaks",
    evidence_table = "working.water_quality_sites",
    where = "e.conductivity > 100")

DBI::dbDisconnect(conn)
} # }