Determine Whether One Window is Contained In Another

Description

Tests whether window A is a subset of window B.

Usage

is.subset.owin(A, B)

Arguments

Details

This function tests whether the window A is a subset of the window B.

The arguments A and B must be window objects (either objects of class "owin", or data that can be coerced to this class by as.owin).

Various algorithms are used, depending on the geometrical type of the two windows.

Note that if B is not rectangular, the algorithm proceeds by discretising A, converting it to a pixel mask using as.mask. In this case the resulting answer is only ``approximately correct''. The accuracy of the approximation can be controlled: see as.mask.

Value

Logical scalar; TRUE if A is a sub-window of B, otherwise FALSE.

Author(s)

Adrian Baddeley adrian@maths.uwa.edu.au http://www.maths.uwa.edu.au/~adrian/ and Rolf Turner rolf@math.unb.ca http://www.math.unb.ca/~rolf

Examples

   w1 <- as.owin(c(0,1,0,1))
   w2 <- as.owin(c(-1,2,-1,2))
   is.subset.owin(w1,w2)  # Returns TRUE.
   is.subset.owin(w2,w1)  # Returns FALSE.