add_spatial_rook: Add rook adjacency from polygons

In multiscape: Multi-Action, Multi-Objective Spatial Planning

Add rook adjacency from polygons

Description

Build and register a rook adjacency relation from planning-unit polygons.

Two planning units are rook-adjacent if they share a boundary segment of positive length. Corner-only contact does not count as rook adjacency.

Usage

add_spatial_rook(x, geometry = NULL, name = "rook", weight = 1)

Arguments

x	A Problem object created with create_problem or another object containing aligned planning-unit polygons.
geometry	Optional sf object with planning-unit polygons and an id column. If NULL, x$data$pu_sf is used.
name	Character string giving the key under which the relation is stored.
weight	Numeric scalar giving the edge weight assigned to each rook adjacency.

Details

Use this function when neighbourhood should be defined by shared polygon edges rather than by point-touching or coordinate-based proximity.

This constructor derives an adjacency graph from polygon geometry using a rook criterion. If planning units i and j share a common edge of non-zero length, then an edge (i,j) is added to the relation.

Let G = (\mathcal{I}, E) denote the resulting graph. Then:

(i,j) \in E \quad \Longleftrightarrow \quad \mathrm{length}(\partial i \cap \partial j) > 0.

All edges receive the same user-supplied weight.

The resulting relation is stored as an undirected spatial relation.

Value

An updated Problem object.

See Also

add_spatial_queen, add_spatial_boundary

Examples

# Load a complete simulated planning problem.
example_data <- load_sim_multiaction()

p <- create_problem(
  pu = example_data$planning_units,
  features = example_data$features,
  dist_features = example_data$dist_features,
  cost = "cost"
)

p <- add_spatial_rook(
  x = p,
  geometry = example_data$planning_units,
  name = "rook",
  weight = 1
)

head(p$data$spatial_relations$rook)

multiscape documentation built on Oct. 12, 2026, 5:08 p.m.