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Reproject location coordinates to a new coordinate reference system

Source: R/occ_reproj.R
occ_reproj.Rd

Reprojects the x/y (longitude/latitude) coordinates of a set of species occurrence records from one coordinate reference system (CRS) to another, and returns the results either as new columns appended to the input data or as replacements for the original coordinate columns.

Usage

occ_reproj(
  data,
  x = "x",
  y = "y",
  from = "EPSG:4326",
  to = NULL,
  replace_cols = FALSE
)

Arguments

data

data.frame or tibble. A table containing occurrence records with at least two columns for the x (longitude) and y (latitude) coordinates.

x

character. Name of the column in data containing the x (longitude) coordinate. Default "x".

y

character. Name of the column in data containing the y (latitude) coordinate. Default "y".

from

character. CRS of the input coordinates, provided as an EPSG code (e.g., "EPSG:4326") or any other CRS string accepted by terra::vect(). Default "EPSG:4326" (WGS84 unprojected).

to

character. CRS to project the coordinates to, provided as an EPSG code (e.g., "EPSG:32617") or any other CRS string accepted by terra::project(). This argument is mandatory; the function will stop with an error if to = NULL.

replace_cols

logical. If TRUE, the original x and y columns in data are overwritten with the reprojected coordinates. If FALSE (default), the reprojected coordinates are appended as new columns x_new and y_new, leaving the original columns unchanged.

Value

A tibble (or data.frame, if replace_cols = TRUE) with the reprojected coordinates. If replace_cols = FALSE, two new columns, x_new and y_new, are added to data. If replace_cols = TRUE, the original x and y columns are replaced in place and the object class of data is preserved.

Details

This function is a convenience wrapper around terra::vect() and terra::project() for reprojecting tabular occurrence coordinates without needing to first convert data into a spatial object. It is useful, for example, when occurrence records are stored in geographic coordinates (e.g., "EPSG:4326") but need to be converted to a projected CRS (e.g., a UTM zone) for distance-based calculations or to match the CRS of environmental raster layers used elsewhere in a species distribution modeling workflow.

See also

project, vect

Examples

if (FALSE) { # \dontrun{
data <- data.frame(
  species = c("sp1", "sp2", "sp3"),
  x = c(-74.1, -73.9, -74.0),
  y = c(4.6, 4.7, 4.65)
)

# Append reprojected coordinates as new columns
occ_reproj(data, x = "x", y = "y", from = "EPSG:4326", to = "EPSG:32618")

# Replace original coordinate columns with reprojected values
occ_reproj(
  data,
  x = "x", y = "y",
  from = "EPSG:4326", to = "EPSG:32618",
  replace_cols = TRUE
)
} # }