| 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.
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a character string indicating if the spatial point pattern is "univariate", "multivariate" or "marked". |
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an swin object describing the sampling window (see swin). |
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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). |
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a vector of x coordinates of points located inside the sampling window. |
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a vector of y coordinates of points located inside the sampling window. |
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(optional) an integer value giving the number of points of the pattern located outside the sampling window. |
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(optional) a vector of x coordinates of points located outside the sampling window. |
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(optional) a vector of y coordinates of points located outside the sampling window. |
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(optional) a vector of the marks attached to points located inside the sampling window. |
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(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