spp {ads} | R Documentation |
Function spp
creates an object of class "spp"
, which represents a
spatial point pattern observed in a finite sampling window (or study region).
The ads
library supports univariate, multivariate and marked point patterns
observed in simple (rectangular or circular) or complex sampling windows.
spp(x, y=NULL, window) spp(x, y=NULL, window, triangles) spp(x, y=NULL, window, marks, int2fac = TRUE) spp(x, y=NULL, window, triangles, marks, int2fac = TRUE)
x,y |
if y=NULL , x is a list of two vectors of point coordinates, else both x and y are atomic vectors of point coordinates. |
window |
a "swin" object or 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 swin ). |
marks |
(optional) a vector of mark values, which may be factor levels or numerical values (see Details). |
int2fac |
if TRUE, integer marks are automatically coerced into factor levels. |
A spatial point pattern is assumed to have been observed within a specific
sampling window (a finite study region) defined by the window
argument. If window
is a simple "swin"
object,
it may be coerced into a complex type by adding a triangles
argument (see swin
). A spatial point pattern may be of 3 different types.
marks
is not given.
marks
is a factor, which levels are interpreted as categorical marks (e.g. colours, species, etc.) attached to points of the pattern.
Integer marks may be automatically coerced into factor levels when argument int2fac = TRUE
.
marks
is a vector of real numbers attached to points of the pattern. Integer values may also be considered as numerical values
if argument int2fac = FALSE
.
An object of class "spp"
describing a spatial point pattern observed in a given sampling window.
|
a character string indicating if the spatial point pattern is "univariate" , "multivariate" or "marked" . |
|
an swin object describing the sampling window (see swin ). |
|
an integer value giving the number of points of the pattern located inside the sampling window (points on the boundary are considered to be inside). |
|
a vector of x coordinates of points located inside the sampling window. |
|
a vector of y coordinates of points located inside the sampling window. |
|
(optional) an integer value giving the number of points of the pattern located outside the sampling window. |
|
(optional) a vector of x coordinates of points located outside the sampling window. |
|
(optional) a vector of y coordinates of points located outside the sampling window. |
|
(optional) a vector of the marks attached to points located inside the sampling window. |
|
(optional) a vector of the marks attached to points located outside the sampling window. |
There are printing, summary and plotting methods for "spp"
objects.
Function spp2ppp(spp.object)
coerces an object of class "spp"
into a ppp.object
suitable for use with package spatstat
.
Goreaud, F. and Pélissier, R. 1999. On explicit formula of edge effect correction for Ripley's K-function. Journal of Vegetation Science, 10:433-438.
data(BPoirier) BP<-BPoirier # univariate pattern in a rectangle of size [0,110] x [0,90] swr<-spp(BP$trees,win=BP$rect) # an alternative using atomic vectors of point coordinates #swr<-spp(BP$trees,win=BP$rect) summary(swr) plot(swr) # univariate pattern in a circle with radius 50 centred on (55,45) swc<-spp(BP$trees,win=c(55,45,50)) summary(swc) plot(swc) plot(swc, out=TRUE) # plot points outside the circle # multivariate pattern in a rectangle of size [0,110] x [0,90] swrm<-spp(BP$trees,win=BP$rect,marks=BP$species) summary(swrm) plot(swrm) plot(swrm, chars=c("b","h","o")) # replace symbols by letters # marked pattern in a rectangle of size [0,110] x [0,90] swrn<-spp(BP$trees,win=BP$rect,marks=BP$dbh) summary(swrn) plot(swrn) # multivariate pattern in a complex sampling window swrt<-spp(BP$trees,win=BP$rect,tri=BP$tri1,marks=BP$species) summary(swrt) plot(swrt) plot(swrt, out=TRUE) # plot points outside the sampling window