Extract.ppx

Extract Subset of Multidimensional Point Pattern

Extract a subset of a multidimensional point pattern.

Usage

# S3 method for ppx
[(x, i, drop=FALSE, ...)

Details

This function extracts a designated subset of a multidimensional point pattern.

The function [.ppx is a method for [ for the class "ppx". It extracts a designated subset of a point pattern. The argument i may be either

• a subset index in the usual R sense: either a numeric vector of positive indices (identifying the points to be retained), a numeric vector of negative indices (identifying the points to be deleted) or a logical vector of length equal to the number of points in the point pattern x. In the latter case, the points (x$x[i], x$y[i]) for which subset[i]=TRUE will be retained, and the others will be deleted.

• a spatial domain of class "boxx" or "box3". Points falling inside this region will be retained.

The argument drop determines whether to remove unused levels of a factor, if the point pattern is multitype (i.e. the marks are a factor) or if the marks are a data frame or hyperframe in which some of the columns are factors.

Use the function unmark to remove marks from a marked point pattern.

See Also

ppx

Aliases

• [.ppx

Examples

# NOT RUN {
   df <- data.frame(x=runif(4),y=runif(4),z=runif(4))
   X <- ppx(data=df, coord.type=c("s","s","t"))
   X[-2]
# }