GeoThinneR (version 1.0.0)

rounding_hashing_thinning: Rounding Hashing Thinning

Description

Performs thinning of geographical coordinates using a hashing approach and rounds the coordinates to create a grid.

Usage

rounding_hashing_thinning(
  coordinates,
  thin_dist = 10,
  trials = 10,
  all_trials = FALSE,
  euclidean = FALSE,
  R = 6371,
  seed = NULL
)

Value

A logical vector indicating which points are kept after the thinning process. If `all_trials` is `TRUE`, a list of logical vectors will be returned, one for each trial.

Arguments

coordinates

A numeric matrix of size (n x 2) containing the longitude and latitude of points, where each row represents a coordinate pair.

thin_dist

A numeric value specifying the distance (in kilometers) within which points should be considered for thinning.

trials

An integer indicating the number of trials to run for the thinning process. More trials may yield better results.

all_trials

A logical value indicating whether to return all trials (`TRUE`) or only the best trial (`FALSE`).

euclidean

Logical value indicating whether to compute the Euclidean distance (`TRUE`) or Haversine distance (`FALSE`, default).

R

A numeric value representing the radius of the Earth in kilometers. Default is set to 6371.0 km.

seed

Optional; an integer seed for reproducibility of results.

Details

This function applies a hashing technique to group coordinates into grid cells, allowing for efficient thinning based on a specified distance. It can run multiple trials to determine the best set of points to keep, or return all trials if specified.

Examples

# Generate random coordinates
set.seed(123)
coordinates <- matrix(runif(20, min = -180, max = 180), ncol = 2) # 10 random points

# Perform rounding hashing thinning
result <- rounding_hashing_thinning(coordinates, thin_dist = 10, trials = 5)
print(result)

# Perform thinning with all trials
all_results <- rounding_hashing_thinning(coordinates, thin_dist = 5000, trials = 5,
                                         all_trials = TRUE)
print(all_results)

# Perform thinning with euclidean distance
result_euclidean <- rounding_hashing_thinning(coordinates, thin_dist = 10,
                                              trials = 5, euclidean = TRUE)
print(result_euclidean)