Get Stream Segments Downstream of a Network Position

Returns all FWA stream segments downstream of a given blue line key and downstream route measure. Uses the fwapg fwa_downstream() ltree comparison.

Usage

frs_network_downstream(
  conn,
  blue_line_key,
  downstream_route_measure,
  table = "whse_basemapping.fwa_stream_networks_sp",
  cols = c("linear_feature_id", "blue_line_key", "waterbody_key", "edge_type",
    "gnis_name", "stream_order", "stream_magnitude", "gradient",
    "downstream_route_measure", "upstream_route_measure", "length_metre",
    "watershed_group_code", "wscode_ltree", "localcode_ltree", "geom"),
  wscode_col = "wscode_ltree",
  localcode_col = "localcode_ltree",
  include_all = FALSE
)

Arguments

conn

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

blue_line_key

Integer. Blue line key of the reference point.

downstream_route_measure

Numeric. Downstream route measure of the reference point.

table

Character. Fully qualified table name. Default "whse_basemapping.fwa_stream_networks_sp".

cols

Character vector of column names to select. Default includes the most commonly used FWA stream attributes.

wscode_col

Character. Name of the watershed code ltree column. Default "wscode_ltree". Use "wscode" for bcfishpass views.

localcode_col

Character. Name of the local code ltree column. Default "localcode_ltree". Use "localcode" for bcfishpass views.

include_all

Logical. If TRUE, include placeholder streams (999 wscode) and unmapped tributaries (NULL localcode). Default FALSE filters these out. Only applied when querying the FWA base table.

Value

An sf data frame of downstream stream segments.

See also

Other traverse: frs_network(), frs_network_upstream(), frs_waterbody_network()

Examples

if (FALSE) { # \dontrun{
conn <- frs_db_conn()
downstream <- frs_network_downstream(conn,
  blue_line_key = 360873822,
  downstream_route_measure = 166030
)
DBI::dbDisconnect(conn)
} # }