calba (version 0.1.2)

ba_simple: Calculate Simple Basal Area

Description

This function calculates the total basal area (conspecific + heterospecific) for a given set of tree data, focusing on the number of focal trees and a radius parameter. The basal area represents the cumulative cross-sectional area of tree trunks, either unadjusted or adjusted for a simple distance-weighted decay model.

Usage

ba_simple(
  sp,
  gx,
  gy,
  ba,
  r,
  dist_weighted = FALSE,
  edge_correction = c("none", "safe"),
  bounds = NULL
)

Value

A list with two numeric vectors:

`con_ba`

A numeric vector representing the cumulative basal area of conspecific trees within the radius.

`total_ba`

A numeric vector representing the cumulative basal area of all trees (conspecific + heterospecific) within the radius.

Arguments

sp

A character vector containing species names for each tree.

gx

A numeric vector of x-coordinates for the trees (e.g., 0 to 10 for realistic spatial data).

gy

A numeric vector of y-coordinates for the trees (e.g., 0 to 10 for realistic spatial data).

ba

A numeric vector of basal area values for the trees (e.g., cross-sectional area at breast height).

r

A numeric scalar for the radius parameter. This parameter represents the maximum distance to consider when summing basal areas of neighboring trees (e.g., 1–5 units for spatially distributed data).

dist_weighted

Logical. If `TRUE`, use the distance-weighted approach (`ba / dist`); if `FALSE`, use the unadjusted `ba`.

edge_correction

Character. Use `"none"` (default) to return all focal trees or `"safe"` to skip neighborhood calculations for trees within `r` of the plot edges and mark their output as `NA`.

bounds

Optional numeric vector `c(xmin, xmax, ymin, ymax)` giving the plot extent. When `NULL`, the range of `gx`/`gy` is used; supply bounds if your data do not span the full plot.

Details

The function either: - Calculates the unadjusted basal area if `dist_weighted = FALSE`. - Applies a simple distance-weighted approach (`ba / dist`) if `dist_weighted = TRUE`.

Examples

# Generate a sample dataset
set.seed(42)  # For reproducibility
sample_data <- data.frame(
  latin = sample(letters[1:4], 100, replace = TRUE),
  gx = runif(100, 0, 10),  # Spatial coordinates between 0 and 10
  gy = runif(100, 0, 10),
  ba = runif(100, 10, 30)  # Basal area between 10 and 30
)

# Calculate with distance weighting
ba_simple(
  sp = sample_data$latin,
  gx = sample_data$gx,
  gy = sample_data$gy,
  ba = sample_data$ba,
  r = 3,  # Radius within the spatial scale
  dist_weighted = TRUE
)

# Calculate without distance weighting
ba_simple(
  sp = sample_data$latin,
  gx = sample_data$gx,
  gy = sample_data$gy,
  ba = sample_data$ba,
  r = 3,
  dist_weighted = FALSE
)