intersect.owin

Intersection, Union or Set Subtraction of Windows

Yields the intersection, union or set subtraction of windows.

Usage

intersect.owin(…, fatal=TRUE, p)
   union.owin(…, p)
   setminus.owin(A, B, …, p)

Details

The function intersect.owin computes the intersection between the windows given in …, while union.owin computes their union. The function setminus.owin computes the intersection of A with the complement of B.

For intersect.owin and union.owin, the arguments … must be either

• window objects of class "owin",

• data that can be coerced to this class by as.owin),

• lists of windows, of class "solist",

• named arguments of as.mask to control the discretisation if required.

For setminus.owin, the arguments … must be named arguments of as.mask.

If the intersection is empty, then if fatal=FALSE the result is NULL, while if fatal=TRUE an error occurs.

See Also

is.subset.owin, overlap.owin, boundingbox, owin.object

Aliases

• intersect.owin
• union.owin
• setminus.owin

Examples

# NOT RUN {
# rectangles
   u <- unit.square()
   v <- owin(c(0.5,3.5), c(0.4,2.5))
# polygon
   data(letterR)
# mask
   m <- as.mask(letterR)

# two rectangles
   intersect.owin(u, v) 
   union.owin(u,v)
   setminus.owin(u,v)

# polygon and rectangle
   intersect.owin(letterR, v)
   union.owin(letterR,v)
   setminus.owin(letterR,v)

# mask and rectangle
   intersect.owin(m, v)
   union.owin(m,v)
   setminus.owin(m,v)

# mask and polygon
   p <- rotate(v, 0.2)
   intersect.owin(m, p)
   union.owin(m,p)
   setminus.owin(m,p)

# two polygons
   A <- letterR
   B <- rotate(letterR, 0.2)
   plot(boundingbox(A,B), main="intersection")
   w <- intersect.owin(A, B)
   plot(w, add=TRUE, col="lightblue")
   plot(A, add=TRUE)
   plot(B, add=TRUE)

   plot(boundingbox(A,B), main="union")
   w <- union.owin(A,B)
   plot(w, add=TRUE, col="lightblue")   
   plot(A, add=TRUE)
   plot(B, add=TRUE)

   plot(boundingbox(A,B), main="set minus")
   w <- setminus.owin(A,B)
   plot(w, add=TRUE, col="lightblue")   
   plot(A, add=TRUE)
   plot(B, add=TRUE)

# intersection and union of three windows
   C <- shift(B, c(0.2, 0.3))
   plot(union.owin(A,B,C))
   plot(intersect.owin(A,B,C))
# }