sitesInNKMFUN: Find All Sites Within n Radius.
In gmiskell/sensor_toolkit: Functions for Managing Sensor Networks

A function for finding all sites within a radius around a location.

1	sitesInNKMFUN(x, id, lat, lon, n, as.list = F)

`id`	Name of the location (as character string).
`lat`	Latitude column.
`lon`	Longitude column.
`n`	Distance radius (in degrees). Kilometre distance can be found using the latitude of the measurement locaition.
`as.list`	Option to unite the selected sites into a string (can be useful for later selection).