SHARK4R (version 1.0.2)

check_zero_positions: Identify samples with zero-valued station coordinates

Description

This function inspects a dataset containing sample coordinates to identify potential issues where longitude or latitude values are zero (0), which typically indicate missing or erroneous station positions. The function can return a summary table, a filtered data frame, or a logical vector highlighting problematic rows. It is useful as a data quality control step before spatial analyses or database imports.

Usage

check_zero_positions(
  data,
  coord = "longitude",
  return_df = FALSE,
  return_logical = FALSE,
  verbose = TRUE
)

Value

A DT datatable, a data.frame, a logical vector, or NULL (if no problems found and return_logical = FALSE).

Arguments

data

A data frame. Must contain sample_longitude_dd and/or sample_latitude_dd.

coord

Character. Which coordinate(s) to check: "longitude", "latitude", or "both". Default = "longitude".

return_df

Logical. If TRUE, return a plain data.frame of problematic rows instead of a DT datatable. Default = FALSE.

return_logical

Logical. If TRUE, return a logical vector of length nrow(data) indicating which rows have zero in the selected coordinate(s). Overrides return_df. Default = FALSE.

verbose

Logical. If TRUE, messages will be displayed during execution. Defaults to TRUE.

Examples

# Example data
df <- data.frame(
  station_name = c("A", "B", "C"),
  sample_longitude_dd = c(15.2, 0, 18.7),
  sample_latitude_dd = c(56.3, 58.1, 0)
)

# Check for zeroes in both coordinates and return as data.frame
check_zero_positions(df, coord = "both", return_df = TRUE)

# Return a logical vector instead of a table
check_zero_positions(df, coord = "both", return_logical = TRUE)