R: Locate points on a map

map.where {maps} | R Documentation

## Locate points on a map

### Description

Returns the region names containing given locations.

### Usage

    map.where(database = "world", x, y, ...)

### Arguments

`database` | character string naming a geographical database, or a list of `x`, `y`, and `names`. See the documentation for map for more details.
`x` | vector of longitudes.
`y` | vector of latitudes.
`...` | Options for `SpatialPolygons2map`, only used if `database` is of type `SpatialPolygonsDataFrame`

.

### Value

A list of character strings, naming the map region that each (longitude, latitude) pair falls into.

### Note

This function may give erroneous results if the database contains enclaves. For instance, a point in San Marino may also be identified as being in Italy.

### Author(s)

Tom Minka

### See Also

`in.polygon`

### Examples

    # NYC
    map.where("state", -73.8, 41)
    # Auckland
    map.where("nz", 174.6, -36.92)
    # find both in the world
    map.where(x = c(174.6, -73.8), y = c(-36.92, 41))
    # with a map object:
    m = map("state", "new york", fill = TRUE, plot = FALSE)
    map.where(m, -73.8, 41)

[Package maps version 3.3.0 Index]