Get elevation from the USGS Elevation Point Query Service

Queries the USGS Elevation Point Query Service for one or more latitude and longitude pairs. Coordinates are interpreted as WGS84 (WKID 4326). Requests are performed in parallel for improved performance when querying multiple points.

Usage

get_usgs_elev(latitude, longitude, units = c("meters", "feet", "m", "ft"))

Arguments

latitude, longitude: Numeric vectors of latitude and longitude in decimal degrees. Latitude values must be between -90 and 90; longitude values must be between -180 and 180. Western longitudes are negative. Inputs must be the same length.
units: Character scalar specifying the output elevation units. Accepted values are "meters", "m", "feet", and "ft". Matching is case insensitive. Defaults to "meters".

Value

A numeric vector of elevations in the requested units, with one element for each input coordinate pair. If an elevation cannot be retrieved for a point, NA_real_ is returned for that location and a warning is issued.

Examples

if (FALSE) { # \dontrun{
get_usgs_elev(
  latitude = 39.102075,
  longitude = -96.594689
)

get_usgs_elev(
  latitude = c(39.102075, 38.8977),
  longitude = c(-96.594689, -77.0365),
  units = "ft"
)
} # }