Compute region anchor positions for grouped layouts

Implements the anchor layout procedure from Section 12. Supports three modes: automatic radial placement, automatic with collision resolution, and manual user-specified anchors.

Usage

layout_regions(
  sf_obj,
  region_col,
  mode = c("auto", "auto_collision", "manual"),
  anchors = NULL,
  initial_layout = NULL,
  preserve_manual = FALSE,
  kappa = 1.8,
  padding = 50000,
  delta = 15000,
  lambda = 0.18,
  eta = 0.18,
  padding_sep = 20000,
  max_iter = 60,
  quantile_p = 0.85,
  centroid_fun = c("centroid", "point_on_surface"),
  quiet = FALSE
)

Arguments

sf_obj: Projected sf object with region column
region_col: Grouping column name
mode: "auto" (radial only), "auto_collision" (radial + solver), or "manual"
anchors: For mode = "manual": data.frame with columns (region_col, anchor_x, anchor_y)
initial_layout: Optional data.frame with columns (region_col, anchor_x, anchor_y), or a grouped layout object. Used when preserve_manual = TRUE.
preserve_manual: If TRUE, use initial_layout as starting anchors before optional collision refinement.
kappa: Radial expansion factor (default 1.8)
padding: Base padding in map units (default 50000)
delta: Log-density scaling factor (default 15000)
lambda: Spring coefficient for collision solver (default 0.18)
eta: Repulsion step size for collision solver (default 0.18)
padding_sep: Minimum separation between blocks (default 20000)
max_iter: Max iterations for collision solver (default 60)
quantile_p: Quantile for block radius estimation (default 0.85)
centroid_fun: "centroid" or "point_on_surface"
quiet: If TRUE, suppress message() output. Default FALSE.

Value

data.frame with region, anchor_x, anchor_y, block_radius, n_units