add_utm_columns function

Add UTM coordinates to a data frame

Add UTM (Universal Transverse Mercator) coordinates to a data frame. This is useful since geostatistical modeling should generally be performed in an equal-distance projection. You can do this yourself separately with the sf::st_as_sf(), sf::st_transform(), and sf::st_coordinates() functions in the sf package.

add_utm_columns(
  dat,
  ll_names = c("longitude", "latitude"),
  ll_crs = 4326,
  utm_names = c("X", "Y"),
  utm_crs = get_crs(dat, ll_names),
  units = c("km", "m")
)

get_crs(dat, ll_names = c("longitude", "latitude"))

Arguments

• dat: Data frame that contains longitude and latitude columns.
• ll_names: Longitude and latitude column names. Note the order.
• ll_crs: Input CRS value for ll_names.
• utm_names: Output column names for the UTM columns.
• utm_crs: Output CRS value for the UTM zone; tries to detect with get_crs() but can be specified manually.
• units: UTM units.

Returns

A copy of the input data frame with new columns for UTM coordinates.

Details

Note that longitudes west of the prime meridian should be encoded asrunning from -180 to 0 degrees.

You may wish to work in km's rather than the standard UTM meters so that the range parameter estimate is not too small, which can cause computational issues. This depends on the the scale of your data.

Examples

d <- data.frame(lat = c(52.1, 53.4), lon = c(-130.0, -131.4))
get_crs(d, c("lon", "lat"))
add_utm_columns(d, c("lon", "lat"))