Description Usage Arguments Details Value Author(s) See Also Examples
Tries to coerce any reasonable kind of data to a spatial point pattern
(an object of class "ppp"
)
for use by the spatstat package).
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22  as.ppp(X, ..., fatal=TRUE)
## S3 method for class 'ppp'
as.ppp(X, ..., fatal=TRUE)
## S3 method for class 'psp'
as.ppp(X, ..., fatal=TRUE)
## S3 method for class 'quad'
as.ppp(X, ..., fatal=TRUE)
## S3 method for class 'matrix'
as.ppp(X, W=NULL, ..., fatal=TRUE)
## S3 method for class 'data.frame'
as.ppp(X, W=NULL, ..., fatal=TRUE)
## S3 method for class 'influence.ppm'
as.ppp(X, ...)
## Default S3 method:
as.ppp(X, W=NULL, ..., fatal=TRUE)

X 
Data which will be converted into a point pattern 
W 
Data which define a window for the pattern,
when 
... 
Ignored. 
fatal 
Logical value specifying what to do if the data cannot be converted. See Details. 
Converts the dataset X
to a point pattern
(an object of class "ppp"
; see ppp.object
for
an overview).
This function is normally used to convert an existing point pattern
dataset, stored in another format, to the "ppp"
format.
To create a new point pattern from raw data such as x,y
coordinates, it is normally easier to use the creator function
ppp
.
The function as.ppp
is generic, with methods for the
classes "ppp"
, "psp"
, "quad"
, "matrix"
,
"data.frame"
and a default method.
The dataset X
may be:
an object of class "ppp"
an object of class "psp"
a point pattern object created by the spatial library
an object of class "quad"
representing a quadrature scheme
(see quad.object
)
a matrix or data frame with at least two columns
a structure with entries x
, y
which are numeric vectors
of equal length
a numeric vector of length 2, interpreted as the coordinates of a single point.
In the last three cases, we need the second argument W
which is converted to a window object
by the function as.owin
.
In the first four cases, W
will be ignored.
If X
is a line segment pattern (an object of class psp
)
the point pattern returned consists of the endpoints of the segments.
If X
is marked then the point pattern returned will also be
marked, the mark associated with a point being the mark of the segment
of which that point was an endpoint.
If X
is a matrix or data frame, the first and second columns will
be interpreted as the x and y coordinates respectively.
Any additional columns will be interpreted as marks.
The argument fatal
indicates what to do when
W
is missing and X
contains no
information about the window. If fatal=TRUE
, a fatal error
will be generated; if fatal=FALSE
, the
value NULL
is returned.
In the spatial library, a point pattern is represented in either of the following formats:
(in spatial versions 1 to 6)
a structure with entries x
, y
xl
, xu
, yl
, yu
(in spatial version 7)
a structure with entries
x
, y
and area
,
where area
is a structure with entries
xl
, xu
, yl
, yu
where x
and y
are vectors of equal length
giving the point coordinates, and xl
, xu
, yl
,
yu
are numbers giving the dimensions of a rectangular window.
Point pattern datasets can also be created by the function
ppp
.
An object of class "ppp"
(see ppp.object
)
describing the point pattern and its window of observation.
The value NULL
may also be returned; see Details.
ppp
, ppp.object
, as.owin
,
owin.object
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15  xy < matrix(runif(40), ncol=2)
pp < as.ppp(xy, c(0,1,0,1))
# VenablesRipley format
# check for 'spatial' package
spatialpath < system.file(package="spatial")
if(nchar(spatialpath) > 0) {
require(spatial)
towns < ppinit("towns.dat")
pp < as.ppp(towns) # converted to our format
detach(package:spatial)
}
xyzt < matrix(runif(40), ncol=4)
Z < as.ppp(xyzt, square(1))

Loading required package: nlme
Loading required package: rpart
spatstat 1.510 (nickname: 'Poetic Licence')
For an introduction to spatstat, type 'beginner'
Note: spatstat version 1.510 is out of date by more than 4 months; we recommend upgrading to the latest version.
Loading required package: spatial
Attaching package: 'spatial'
The following object is masked from 'package:spatstat':
Strauss
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