Check if stations are reported as nominal positions — check_nominal

This function attempts to determine whether stations in a dataset are reported using nominal positions (i.e., generic or repeated coordinates across events), rather than actual measured coordinates. It compares the number of unique sampling dates with the number of unique station coordinates.

Usage

check_nominal_station(data, verbose = TRUE)

Arguments

data: A data frame containing at least the columns: sample_date, station_name, sample_longitude_dd, and sample_latitude_dd.
verbose: Logical. If TRUE, messages will be displayed during execution. Defaults to TRUE.

Value

A data frame with distinct station names and their corresponding latitude/longitude positions, if nominal positions are suspected. Otherwise, returns NULL.

Details

If the number of unique sampling dates is larger than the number of unique station coordinates, the function suspects nominal station positions and issues a warning.

Examples

df <- data.frame(
  sample_date = rep(seq.Date(Sys.Date(), by = "day", length.out = 3), each = 2),
  station_name = rep(c("ST1", "ST2"), 3),
  sample_longitude_dd = rep(c(15.0, 16.0), 3),
  sample_latitude_dd = rep(c(58.5, 58.6), 3)
)
check_nominal_station(df)
#> WARNING: Suspected nominal positions reported! Is this correct?
#>   STATION LON  LAT
#> 1     ST1  15 58.5
#> 2     ST2  16 58.6