identify.map {maps}

Identify regions on a map

Description

Identifies the map regions clicked by the user.

Usage

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

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.

Author(s)

Tom Minka

See Also

identify, map.where

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)))