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 amarksvector 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"))