Convert Point Pattern Marks from Numeric to Factor
Transform the marks of a marked point pattern from numeric values into a factor.
## S3 method for class 'ppp': cut(x, \dots)
This simple function applies the generic
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
- A multitype point pattern, that is, a point pattern object
"ppp") with a
marksvector that is a factor.
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"))