Creates a deep copy of a Quadtree.
# S4 method for Quadtree
copy(x)Arguments
- x
a
Quadtree
Value
a Quadtree
Details
This function creates a deep copy of a Quadtree
object. The Quadtree class contains a pointer to a
CppQuadtree C++ object. If a copy is attempted by simply
assigning the quadtree to a new variable, it will simply make a copy of the
pointer, and both variables will point to the same
CppQuadtree. Thus, changes made to one will also change the
other. See "Examples" for a demonstration of this.
This function creates a deep copy by copying the entire quadtree, and should be used whenever a copy of a quadtree is desired.
Examples
library(quadtree)
habitat <- terra::rast(system.file("extdata", "habitat.tif", package="quadtree"))
# create a quadtree, then create a shallow copy and a deep copy
qt1 <- quadtree(habitat, split_threshold = .1)
plot(qt1)
qt2 <- qt1 # SHALLOW copy
qt3 <- copy(qt1) # DEEP copy
# change the values of qt1 so we can observe how this affects qt2 and qt3
transform_values(qt1, function(x) 1 - x)
# plot it out to see what happened
old_par <- par(mfrow = c(1, 3))
plot(qt1, main = "qt1", border_col = "transparent")
plot(qt2, main = "qt2", border_col = "transparent")
plot(qt3, main = "qt3", border_col = "transparent")
par(old_par)
# qt2 was modified but qt3 was not