Generate ring regions between a boundary and its outer buffer

Computes spatial ring-shaped regions by subtracting the original boundary polygons from their corresponding outer buffered polygons. If the outer_boundary is not supplied, it will be automatically computed using getOuterBoundary(). This is useful for analyzing periphery-enriched cell types or gradient-based features near a boundary.

Usage

getRingRegion(boundary = NULL, outer_boundary = NULL, ...)

Arguments

boundary

A data frame of boundary points (with columns x, y, region_id) or an sf object.

outer_boundary

Optional sf object containing buffered (outer) boundary polygons. If not provided, it will be automatically computed using getOuterBoundary().

...

Additional arguments passed to getOuterBoundary() if outer_boundary is not provided.

Value

An sf object containing the ring-shaped spatial regions generated by subtracting each inner boundary polygon from its corresponding outer boundary polygon.

Examples

# Load coordinates
coords <- readRDS(system.file("extdata", "MouseBrainCoords.rds",
    package = "SpNeigh"
))
head(coords)
#>          x        y cell cluster
#> 1 1898.815 2540.963    1       4
#> 2 1895.305 2532.627    2       4
#> 3 2368.073 2534.409    3       2
#> 4 1903.726 2560.010    4       4
#> 5 1917.481 2543.132    5       4
#> 6 1926.540 2560.044    6       4

# Get boundary points of cluster 2
boundary_points <- getBoundary(data = coords, one_cluster = 2)

# Automatically compute outer boundary and get rings
ring_regions <- getRingRegion(boundary = boundary_points, dist = 100)
plot(ring_regions)


# Or provide both inner and outer boundaries explicitly
outer <- getOuterBoundary(boundary_points, dist = 100)
rings <- getRingRegion(boundary = boundary_points, outer_boundary = outer)
plot(rings)