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Convert georeferenced UCDP data to an sf object

Source: R/spatial.R
ucdp_as_sf.Rd

ucdp_as_sf() recognizes common UCDP coordinate columns and converts them to point geometry. The original ucdp_source provenance attribute is retained, making the result suitable for later spatial joins, including workflows built around the released priogrid package or a future priogridR package.

Usage

ucdp_as_sf(
  data,
  longitude = NULL,
  latitude = NULL,
  crs = 4326,
  remove = FALSE,
  missing = c("keep", "drop", "error")
)

Arguments

data

A data frame containing coordinates, or an existing sf object.

longitude, latitude

Coordinate column names. When omitted, common UCDP names are detected automatically.

crs

Coordinate reference system passed to sf::st_as_sf(). UCDP GED coordinates use EPSG 4326.

remove

Remove the source coordinate columns?

missing

How to handle missing coordinates: retain them as empty geometries, drop their rows, or raise an error.

Value

An sf object with point geometry.

Examples

events <- data.frame(
  id = 1:3, longitude = c(10, 20, NA), latitude = c(50, 60, NA)
)
if (requireNamespace("sf", quietly = TRUE)) {
  events_sf <- ucdp_as_sf(events, missing = "drop")
  sf::st_crs(events_sf)
}
#> Coordinate Reference System:
#>   User input: EPSG:4326 
#>   wkt:
#> GEOGCRS["WGS 84",
#>     ENSEMBLE["World Geodetic System 1984 ensemble",
#>         MEMBER["World Geodetic System 1984 (Transit)"],
#>         MEMBER["World Geodetic System 1984 (G730)"],
#>         MEMBER["World Geodetic System 1984 (G873)"],
#>         MEMBER["World Geodetic System 1984 (G1150)"],
#>         MEMBER["World Geodetic System 1984 (G1674)"],
#>         MEMBER["World Geodetic System 1984 (G1762)"],
#>         MEMBER["World Geodetic System 1984 (G2139)"],
#>         ELLIPSOID["WGS 84",6378137,298.257223563,
#>             LENGTHUNIT["metre",1]],
#>         ENSEMBLEACCURACY[2.0]],
#>     PRIMEM["Greenwich",0,
#>         ANGLEUNIT["degree",0.0174532925199433]],
#>     CS[ellipsoidal,2],
#>         AXIS["geodetic latitude (Lat)",north,
#>             ORDER[1],
#>             ANGLEUNIT["degree",0.0174532925199433]],
#>         AXIS["geodetic longitude (Lon)",east,
#>             ORDER[2],
#>             ANGLEUNIT["degree",0.0174532925199433]],
#>     USAGE[
#>         SCOPE["Horizontal component of 3D system."],
#>         AREA["World."],
#>         BBOX[-90,-180,90,180]],
#>     ID["EPSG",4326]]