Identify regions on a map

Identifies the map regions clicked by the user.

Usage

# S3 method for class 'map'
identify(x, n = 1, index = FALSE, ...)

Author

Tom Minka

Arguments

x: a map object containing named polygons.
n: the number of clicks to wait for.
index: If TRUE, returns the index of the polygon, rather than its name.
...: additional arguments passed to identify.default.

Details

The current algorithm is somewhat crude — selects the region whose centroid is closest to the click. A more sophisticated approach would use map.where.

Value

a character vector of length n, naming the selected regions.

Examples

identify(map("state", fill = TRUE, col = 0))
if(require(mapproj))
  identify(map("world", proj = "lagrange", fill = TRUE, col = 0, wrap=c(-180,180,-90)))