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Verify downstream state before modelling a watershed group

Source: R/lnk_wsg_downstream_check.R
lnk_wsg_downstream_check.Rd

link computes accessibility by reading the already-persisted barriers of the watershed groups downstream of the focal one. Modelling a WSG before its downstream neighbours writes streams_access / streams_mapping_code marking segments accessible that are in fact dammed off — and exits cleanly, so the wrong answer is indistinguishable from a right one.

Usage

lnk_wsg_downstream_check(
  conn,
  aoi,
  cfg,
  loaded,
  on_fail = c("error", "warn", "ignore"),
  override = NA_character_,
  outlets = fresh::frs_wsg_outlets()
)

Arguments

conn

DBI connection to the modelling database.

aoi

Watershed group code.

cfg

An lnk_config; supplies the persist schema.

loaded

Output of lnk_load_overrides(); supplies the CABD edit CSVs.

on_fail

"error" (default), "warn", or "ignore". Use "warn" for multi-host runs where downstream groups are legitimately mid-flight on another host and a post-consolidate recompute settles access afterwards.

override

Character justification. Non-empty proceeds despite failure and records the reason. A bare TRUE is rejected on purpose: the justification is the mechanism, and an override without one is the hole this is meant to close.

outlets

Per-group outlet points; defaults to fresh::frs_wsg_outlets().

Value

Invisibly, a list with aoi, status, dams, wsgs_missing, note and elapsed_s.

Details

This checks the precondition instead of asking the operator to assert it: find the blocking dams on the focal WSG's downstream flow path, and confirm each is already persisted as a barrier.

Three outcomes:

  • pass — no unpersisted blocking dam downstream. The common case.

  • fail — there are; stop and name them (or warn, per on_fail).

  • override — proceed on a stated assumption, which is recorded in the run log (link#127) so lnk_log_read() can later report that this network was built assuming those dams do not block.

See also

Other wsg: lnk_wsg_resolve()

Examples

if (FALSE) { # \dontrun{
conn <- lnk_db_conn()
cfg <- lnk_config("default")
loaded <- lnk_load_overrides(cfg)

# Verify before a long run.
lnk_wsg_downstream_check(conn, "PARS", cfg, loaded)

# Multi-host: defer to the post-consolidate recompute, but record it.
lnk_wsg_downstream_check(conn, "PARS", cfg, loaded, on_fail = "warn")
} # }