ifcb_is_near_land: Determine if Positions are Near Land

In sharksmhi/SHARK4R: Retrieving, Analyzing, and Validating Marine Data from SHARK and Nordic Microalgae

Determine if Positions are Near Land

Description

Determines whether given positions are near land based on a coastline shape file. The Natural Earth 1:50m land vectors are included as default shapefile in SHARK4R.

Usage

ifcb_is_near_land(
  latitudes,
  longitudes,
  distance = 500,
  shape = NULL,
  crs = 4326,
  utm_zone = 33,
  remove_small_islands = TRUE,
  small_island_threshold = 2e+06
)

Arguments

latitudes	Numeric vector of latitudes for positions.
longitudes	Numeric vector of longitudes for positions.
distance	Buffer distance in meters around the coastline. Default is 500 m.
shape	Optional path to a shapefile containing coastline data. If provided, the function will use this shapefile instead of the default Natural Earth 1:50m land vectors. Using a more detailed shapefile allows for a smaller buffer distance. For detailed European coastlines, download polygons from the EEA at https://www.eea.europa.eu/data-and-maps/data/eea-coastline-for-analysis-2/gis-data/eea-coastline-polygon. For more detailed world maps, download from Natural Earth at https://www.naturalearthdata.com/downloads/10m-physical-vectors/.
crs	Coordinate reference system (CRS) to use for positions and output. Default is EPSG code 4326 (WGS84).
utm_zone	UTM zone for buffering the coastline. Default is 33 (between 12°E and 18°E, northern hemisphere).
remove_small_islands	Logical indicating whether to remove small islands from the coastline if a custom shapefile is provided. Default is TRUE.
small_island_threshold	Area threshold in square meters below which islands will be considered small and removed, if remove_small_islands is set to TRUE. Default is 2 sqkm.

Details

This function calculates a buffered area around the coastline and checks if given positions (specified by longitudes and latitudes) are within this buffer or intersect with land.

This function is re-exported from the iRfcb package available at https://github.com/EuropeanIFCBGroup/iRfcb

Value

Logical vector indicating whether each position is near land.

Examples

# Define coordinates
latitudes <- c(62.500353, 58.964498, 57.638725, 56.575338)
longitudes <- c(17.845993, 20.394418, 18.284523, 16.227174)

# Call the function
near_land <- ifcb_is_near_land(latitudes, longitudes, distance = 300, crs = 4326)

# Print the result
print(near_land)

sharksmhi/SHARK4R documentation built on Jan. 9, 2025, 5:15 p.m.