cirwin: Create a window on the circle
In adchSTATS/spatstatciradd: Additions to spatstat

Creates an object of class "cirwin" representing an observation window on the circle

1	cirwin(type = "circle", intervals)

`type`	The type of window to be created. Can be either the full circle or a subset and should be "`circle`" respectively "`arcs`". If type is "`circle`" the second argument `intervals` will be ignored
`intervals`	Only required for `type="arcs"`. A vector or matrix like object with length 2 respectively number of columns equal to `2*n`, where `n` is some positive integer If specified as a vector (or matrix) the entries (columns) should be alternating between lower and upper bound, starting with the lower bound.