validate_crs {arcgisutils}

Validate CRS object

Description

Takes a representation of a CRS and ensures that it is a valid one. The CRS is validated using sf::st_crs() if it cannot be validated, a null CRS is returned.

Usage

validate_crs(crs, arg = rlang::caller_arg(crs), call = rlang::caller_env())

Arguments

crs

a representation of a coordinate reference system.

arg

An argument name in the current function.

call

The execution environment of a currently running function, e.g. call = caller_env(). The corresponding function call is retrieved and mentioned in error messages as the source of the error.

You only need to supply call when throwing a condition from a helper function which wouldn't be relevant to mention in the message.

Can also be NULL or a defused function call to respectively not display any call or hard-code a code to display.

For more information about error calls, see Including function calls in error messages.

Details

See sf::st_crs() for more details on valid representations.

Value

Returns a list of length 1 with an element named spatialReference which is itself a named list.

If the provided CRS returns a valid well-known ID (WKID) spatialReference contains a named element called wkid which is the integer value of the WKID. If the WKID is not known but the CRS returned is a valid well-known text representation the wkid field is NA and another field wkt contains the valid wkt.

Examples

# using epsg code integer or string representation
validate_crs(3857)
validate_crs("EPSG:4326")

# using a custom proj4 string
proj4string <- "+proj=longlat +datum=WGS84 +no_defs"

crs <- validate_crs(proj4string)

# using wkt2 (from above result)
crs <- validate_crs(crs$spatialReference$wkt)