swin {ads}R Documentation

Creating a sampling window

Description

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.

Usage

 swin(window, triangles)
 owin2swin(w)

Arguments

window

a vector defining the limits of a simple sampling window: c(xmin,ymin,xmax,ymax) for a rectangle ; c(x0,y0,r0) for a circle.

triangles

(optional) a list of triangles removed from a simple initial window to define a complex sampling window (see Details).

'

w

a "owin" object from package spatstat.geom.

Details

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.

Value

An object of class "swin" describing the sampling window. It may be of four different types with different arguments:

$type

a vector of two character strings defining the type of sampling window among c("simple","rectangle"), c("simple","circle"), c("complex","rectangle") or c("complex","circle").

$xmin,$ymin,$xmax,$ymax

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

$x0,$y0,$r0

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

$triangles

(optional) vertices coordinates of triangles for a complex sampling window (see details).

Note

There are printing, summary and plotting methods for "swin" objects.
Function owin2swin converts an owin.object from package spatstat.geom into an "swin" object.

Author(s)

Raphael.Pelissier@ird.fr

References

Goreaud, F. and P?Pelissier, R. 1999. On explicit formula of edge effect correction for Ripley's K-function. Journal of Vegetation Science, 10:433-438.

See Also

area.swin, inside.swin, spp

Examples

  ## 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)

[Package ads version 1.5-5 Index]