Add boundary polygons or linestrings to a spatial plot

Overlays boundary polygons or linestrings on a spatial ggplot2 plot. This function adds an sf geometry layer to display complete boundary shapes for visualizing spatial clusters, rings, or enriched zones.

Usage

addBoundaryPoly(
  boundary_poly,
  color_boundary = "black",
  linewidth_boundary = 1.5
)

Arguments

boundary_poly

An sf object containing POLYGON or LINESTRING geometries and a region_id column.

color_boundary

Color for boundary lines. Default is "black".

linewidth_boundary

Numeric. Line width for boundary outlines. Default is 1.5.

Value

A ggplot2::geom_sf layer that can be added to an existing plot.

Examples

coords <- readRDS(system.file("extdata", "MouseBrainCoords.rds",
    package = "SpNeigh"
))

boundary_points <- getBoundary(
    data = coords, one_cluster = 2,
    subregion_method = "dbscan",
    eps = 120, minPts = 10
)
boundary_polys <- buildBoundaryPoly(boundary_points)

# Add boundary polygons to the plot
plotBoundary(coords) +
    addBoundaryPoly(boundary_polys, color_boundary = "blue")