Stations along a CalCOFI line, ordered nearshore to offshore

A transect here is a CalCOFI line, ordered by station number ascending, which is nearshore → offshore (calcofi4r treats station > 60 as offshore; station 100 on line 76.7 sits at roughly -124.3° lon). That is well defined for every cruise without asking the user to pick endpoints, which is what makes a whole archive of sections pre-renderable.

Usage

cc_transect_stations(
  con,
  line,
  cruise_key = NULL,
  dataset_key = "calcofi_ctd-cast",
  x = c("occupied", "line")
)

Arguments

con

DuckDB connection to a release (see cc_get_db()).

line

CalCOFI line, e.g. 93.3.

cruise_key

cruise to restrict to; NULL for every cruise on the line.

dataset_key

source dataset (default "calcofi_ctd-cast").

x

"occupied" (default) or "line" — see above.

Value

Tibble: cruise_key, grid_key, sta, lon, lat, datetime, data_stage, dist_km.

Details

order_occ — the order stations were occupied during the cruise — is deliberately NOT used: it is the ship's track, so its direction is whichever way the ship steamed, and it is NULL on roughly half the release's cast rows.

The x argument

x = "occupied" (default) measures distance between the stations this cruise actually occupied, so the section fills the plot and shows the data at its largest. x = "line" measures each station's distance along the FULL line geometry, so two cruises that sampled different subsets are directly comparable in width — at the cost of blank space where a cruise stopped short. That matters: line 93.3 has not been sampled past station 90 since 2025-01, though 113 of the 130 cruises before that reached station 120, so recent sections silently span a shorter distance than historical ones.