Which GNIS stream names collide across watershed groups?

GNIS names repeat across BC, so a report search by stream name drags in reports about a same-named stream elsewhere. This reports, for each seed name, how many watershed groups carry it. Names in one group only are safe to search by name; the rest need a geographic qualifier and a coordinate check on every hit.

Usage

knw_gnis_collisions(
  conn,
  stream_names,
  wsg_code,
  table = "bcfishpass.streams",
  pattern = "River|Creek|Lake"
)

Arguments

conn

A DBI connection.

stream_names

character seed stream names, as they appear in gnis_name.

wsg_code

character(1) the watershed group being worked.

table

character(1) a table carrying both gnis_name and watershed_group_code. Default "bcfishpass.streams".

pattern

character(1) regular expression a seed name must match to be checked; the default keeps rivers, creeks and lakes. NULL checks all.

Value

A tibble with one row per seed name found: gnis_name, n_wsg, wsgs (comma-joined, sorted) and wsg_only (TRUE when the name occurs in wsg_code and nowhere else). Names absent from table are returned in attribute "not_found".

Examples

if (requireNamespace("duckdb", quietly = TRUE)) {
con <- DBI::dbConnect(duckdb::duckdb())
DBI::dbWriteTable(con, "streams", data.frame(
  gnis_name = c("Boulder Creek", "Boulder Creek", "Wildmare Creek"),
  watershed_group_code = c("PINE", "LNTH", "PINE")))
knw_gnis_collisions(con, c("Boulder Creek", "Wildmare Creek", "Ghost Creek"),
                    "PINE", table = "streams")
DBI::dbDisconnect(con, shutdown = TRUE)
}
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