add_utm_columns: Add UTM coordinates to a data frame

In pbs-assess/sdmTMB: Spatial and Spatiotemporal SPDE-Based GLMMs with 'TMB'

Add UTM coordinates to a data frame

Description

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.

Usage

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.

Details

Note that longitudes west of the prime meridian should be encoded as running 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.

Value

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

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"))

pbs-assess/sdmTMB documentation built on Dec. 20, 2024, 1:51 p.m.