Create contour plot.

Creates a contour plot using values of a specified variable associated with coordinates in the forest stand.

contour_plot(
  grid_vals,
  value,
  edge_handling = "none",
  rad = NULL,
  max_x = NULL,
  max_y = NULL
)

Arguments

grid_vals	Data frame containing coordinates and values of the contour variable for a series of points. Columns containing x and y coordinates must be named x_coord and y_coord respectively but the name of the contour variable column can be anything.
value	Name of contour variable column as a string.

Value

A contour plot will appear in the plotting window.

Details

This function takes point estimates of some variable and interpolates a continuous contour plot across the forest stand. For some variables, such as soil nutrient levels, the contour will remain accurate up to the stand boundary. However, if the variable represents a summary of the neighborhood around the points such as local tree density, any point whose neighborhood overlaps the stand boundary will be an underestimate. In the latter case, we recommend users correct for edge effects in their implementation of neighborhood_summary()

Examples

library(dplyr, warn.conflicts = F)
#> Warning: package 'dplyr' was built under R version 4.1.2
# Create coordinate grid
locations <- data.frame(
  loc_id = paste("A", 1:441, sep = ""),
  x_coord = rep(seq(0, 100, 5), times = 21),
  y_coord = rep(seq(0, 100, 5), each = 21))
  
# Calculate density for each point
nbhds <- neighborhoods(mapping, stands = "AB08", radius = 10,
                       coords = locations)
nbhd_summ <- neighborhood_summary(nbhds, "loc_id", 10, "angular",
                                  edge_correction = T, x_limit = 100,
                                  y_limit = 100)

# Format data for contour_plot
grid_data <- locations %>%
  left_join(nbhd_summ %>%
    select(loc_id, all_angle_sum),
    by = "loc_id") %>%
  select(-loc_id)

# Create contour plot
contour_plot(grid_data, "all_angle_sum")