Plot a Quadtree — plot • quadtree

Plots a Quadtree.

# S4 method for Quadtree,missing
plot(
  x,
  add = FALSE,
  col = NULL,
  alpha = NULL,
  nb_line_col = NULL,
  border_col = "black",
  border_lwd = 0.4,
  xlim = NULL,
  ylim = NULL,
  zlim = NULL,
  crop = FALSE,
  na_col = "white",
  adj_mar_auto = 6,
  legend = TRUE,
  legend_args = list(),
  ...
)

Arguments

x: a Quadtree
add: boolean; if FALSE (the default) a new plot is created. If TRUE, the plot is added to the existing plot.
col: character vector; the colors that will be used to create the color ramp used in the plot. If no argument is provided, terrain.colors(100, rev = TRUE) is used.
alpha: numeric; transparency of the cell colors. Must be in the range 0-1, where 0 is fully transparent and 1 is fully opaque. If NULL (the default) it sets alpha to 1.
nb_line_col: character; the color of the lines drawn between neighboring cells. If NULL (the default), these lines are not plotted.
border_col: character; the color to use for the cell borders. Use "transparent" if you don't want borders to be shown. Default is "black".
border_lwd: numeric; the line width of the cell borders. Default is .4.
xlim: two-element numeric vector; defines the minimum and maximum values of the x axis. Note that this overrides the crop parameter.
ylim: two-element numeric vector; defines the minimum and maximum values of the y axis. Note that this overrides the crop parameter.
zlim: two-element numeric vector; defines how the colors are assigned to the cell values. The first color in col will correspond to zlim[1] and the last color in col will correspond to zlim[2]. If zlim does not encompass the entire range of cell values, cells that have values outside of the range specified by zlim will be treated as NA cells. If this value is NULL (the default), it uses the min and max cell values.
crop: boolean; if TRUE, only displays the extent of the original raster, thus ignoring any of the NA cells that were added to pad the raster before making the quadtree. Ignored if either xlim or ylim are non-NULL.
na_col: character; the color to use for NA cells. If NULL, NA cells are not plotted. Default is "white".
adj_mar_auto: numeric; checks the size of the right margin (par("mar")[4]) - if it is less than the provided value and legend is TRUE, then it sets it to be the provided value in order to make room for the legend (after plotting, it resets it to its original value). If NULL, the margin is not adjusted. Default is 6.
legend: boolean; if TRUE (the default) a legend is plotted in the right margin.
legend_args: named list; contains arguments that are sent to the add_legend() function. See the help page for add_legend() for the parameters. Note that zlim, cols, and alpha are supplied automatically, so if the list contains elements named zlim, cols, or alpha the user-provided values will be ignored.
...: arguments passed to the default plot() function

Value

no return value

Details

See 'Examples' for demonstrations of how the various options can be used.

Examples

library(quadtree)
habitat <- terra::rast(system.file("extdata", "habitat.tif", package="quadtree"))

# create quadtree
qt <- quadtree(habitat, split_threshold = .1, adj_type = "expand")

#####################################
# DEFAULT
#####################################

# default - no additional parameters provided
plot(qt)


#####################################
# CHANGE PLOT EXTENT
#####################################

# note that additional parameters like 'main', 'xlab', 'ylab', etc. will be
# passed to the default 'plot()' function

# crop extent to the original extent of the raster
plot(qt, crop = TRUE, main = "cropped")


# crop and don't plot NA cells
plot(qt, crop = TRUE, na_col = NULL, main = "cropped")


# use 'xlim' and 'ylim' to zoom in on an area
plot(qt, xlim = c(10000, 20000), ylim = c(20000, 30000), main = "zoomed in")


#####################################
# COLORS AND BORDERS
#####################################

# change border color and width
plot(qt, border_col = "transparent") # no borders

plot(qt, border_col = "gray60") # gray borders

plot(qt, border_lwd = .3) # change line thickness of borders


# change color palette
plot(qt, col = c("blue", "yellow", "red"))

plot(qt, col = hcl.colors(100))

plot(qt, col = c("black", "white"))


# change color transparency
plot(qt, alpha = .5)

plot(qt, col = c("blue", "yellow", "red"), alpha = .5)


# change color of NA cells
plot(qt, na_col = "lavender")


# don't plot NA cells at all
plot(qt, na_col = NULL)


# change 'zlim'
plot(qt, zlim = c(0, 5))

plot(qt, zlim = c(.2, .7))


#####################################
# SHOW NEIGHBOR CONNECTIONS
#####################################

# plot all neighbor connections
plot(qt, nb_line_col = "black", border_col = "gray60")


# don't plot connections to NA cells
plot(qt, nb_line_col = "black", border_col = "gray60", na_col = NULL)


#####################################
# LEGEND
#####################################

# no legend
plot(qt, legend = FALSE)

# increase right margin size
plot(qt, adj_mar_auto = 10)


# use 'legend_args' to customize the legend
plot(qt, adj_mar_auto = 10,
     legend_args = list(lgd_ht_pct = .8, bar_wd_pct = .4))