cut.ppp
Convert Point Pattern Marks from Numeric to Factor
Transform the marks of a marked point pattern from numeric values into a factor.
Usage
## S3 method for class 'ppp':
cut(x, \dots)
Arguments
- x
- A two-dimensional point pattern.
An object of class
"ppp"
. This should be a marked point pattern, and the marks would normally be numerical values. - ...
- Arguments passed to
cut.default
. They determine the breakpoints for the mapping from numerical values to factor values. Seecut.default
.
Details
This simple function applies the generic cut
operation
to the marks of the point pattern x
. The range of values
of the numerical marks is divided into several intervals, and each
interval is associated with a level of a factor.
The result is a
marked point pattern, with the same window and point locations as
x
, but with the numeric mark of each point discretised
by replacing it by the factor level.
This function is a convenient way to transform a marked point pattern which has numeric marks into a multitype point pattern, for example to plot it or analyse it. See the examples.
To select some points from a point pattern, use the subset operator
[.ppp
instead.
Value
- A multitype point pattern, that is, a point pattern object
(of class
"ppp"
) with amarks
vector that is a factor.
See Also
Examples
data(longleaf)
# Longleaf Pines data
# the marks are positive real numbers indicating tree diameters.
<testonly># smaller dataset
longleaf <- longleaf[seq(1, longleaf$n, by=80)]</testonly>
plot(longleaf)
# cut the range of tree diameters into three intervals
long3 <- cut(longleaf, 3)
plot(long3)
# adult trees defined to have diameter at least 30 cm
long2 <- cut(longleaf, breaks=c(0,30,100), labels=c("Sapling", "Adult"))
plot(long2)
plot(long2, cols=c("green","blue"))