swin {ads}  R Documentation 
Function swin
creates an object of class "swin"
, which represents
the sampling window (or study region) in which a spatial point pattern was
observed. The ads
library supports simple (rectangular or circular) and complex
sampling windows.
swin(window, triangles) owin2swin(w)
window 
a vector defining the limits of a simple sampling window: 
triangles 
(optional) a list of triangles removed from a simple initial window to define a complex sampling window (see Details). 
'
w 
a 
A sampling window may be of simple or complex type. A simple sampling window may be a rectangle or a circle. A complex sampling window is defined by removing triangular surfaces from a simple (rectangular or circular) initial sampling window.
rectangular window:
window=c(ximn,ymin,xmax,ymax)
a vector of length 4 giving the coordinates (ximn,ymin) and (xmax,ymax)
of the origin and the opposite corner of a rectangle.
circular window:
window=c(x0,y0,r0)
a vector of length 3 giving the coordinates (x0,y0)
of the centre and the radius r0 of a circle.
complex window:
triangles
is a list of 6 variables giving the vertices coordinates
(ax,ay,bx,by,cx,cy) of the triangles to remove from a simple (rectangular or circular) initial window. The triangles may be removed
near the boundary of a rectangular window in order to design a polygonal sampling window, or within a rectangle
or a circle, to delineating holes in the initial sampling window (see Examples). The triangles do not overlap each other, nor overlap boundary
of the initial sampling window. Any polygon (possibly with holes) can be decomposed into contiguous triangles using triangulate
.
An object of class "swin"
describing the sampling window. It may be of four different types
with different arguments:

a vector of two character strings defining the type of sampling window among 

(optional) coordinates of the origin and the opposite corner for a rectangular sampling window (see details). 

(optional) coordinates of the centre and radius for a circular sampling window (see details). 

(optional) vertices coordinates of triangles for a complex sampling window (see details). 
There are printing, summary and plotting methods for "swin"
objects.
Function owin2swin
converts an owin.object
from package spatstat.geom
into an "swin"
object.
Goreaud, F. and P?Pelissier, R. 1999. On explicit formula of edge effect correction for Ripley's Kfunction. Journal of Vegetation Science, 10:433438.
## Not run: rectangle of size [0,110] x [0,90] wr < swin(c(0,0,110,90)) summary(wr) plot(wr) ## Not run: circle with radius 50 centred on (55,45) wc < swin(c(55,45,50)) summary(wc) plot(wc) ## Not run: polygon (diamond shape) t1 < c(0,0,55,0,0,45) t2 < c(55,0,110,0,110,45) t3 < c(0,45,0,90,55,90) t4 < c(55,90,110,90,110,45) wp < swin(wr, rbind(t1,t2,t3,t4)) summary(wp) plot(wp) ## Not run: rectangle with a hole h1 < c(25,45,55,75,85,45) h2 < c(25,45,55,15,85,45) wrh < swin(wr, rbind(h1,h2)) summary(wrh) plot(wrh) ## Not run: circle with a hole wch < swin(wc, rbind(h1,h2)) summary(wch) plot(wch) ## Not run: converting an owin object from spatstat.geom data(demopat) demo.swin<owin2swin(demopat$window) plot(demo.swin)