mc_boundary: Cost-limit boundaries around origin locations

In movecost: Calculation of Slope-Dependant Accumulated Cost Surface, Least-Cost Paths, Least-Cost Corridors, Least-Cost Networks Related to Human Movement Across the Landscape

Cost-limit boundaries around origin locations

Description

Delineates, around each origin location, the area reachable within a given cost limit (for instance, the 30-minute walking catchment), reusing the graph stored in a mc_surface object. The accumulated cost surfaces for all origins are obtained with a single multi-source graph query, so the function scales efficiently with the number of origins (movecost <= 2.x recomputed the whole conductance matrix for each call).

Usage

mc_boundary(surface, origin, limit = NULL, time = "h")

Arguments

surface	a movecost_surface object created by mc_surface.
origin	origin location(s) (sf points, SpatVector, or legacy SpatialPointsDataFrame).
limit	cost limit defining the boundary, in the unit of the cost function (for time-based functions, in the unit selected via time); if NULL (default), one tenth of the range of accumulated values across all origins is used.
time	unit for time-based cost functions: "h" (hours, default) or "m" (minutes).

Details

Unlike movecost <= 2.x, which derived the boundary from contour lines of a combined minimum-cost surface, version 3.0 polygonises each origin's reachable area directly (cells with accumulated cost <= limit), which yields closed polygons by construction and allows area and perimeter to be computed exactly. Overlapping catchments of different origins are preserved as separate (overlapping) polygons.

Value

An object of class movecost_boundary, a list with components

• boundaries: sf polygons (one feature per origin) with origin_id, limit, area (m^2) and perimeter (m) attributes;

• accum: the minimum accumulated cost surface across origins (SpatRaster), useful for plotting;

• origin: the origin location(s) (sf);

• metadata used by the plot method.

Plot it at any time with plot() (see plot.movecost_boundary).

See Also

mc_surface, plot.movecost_boundary

Examples

dtm <- mc_volc()
destin <- mc_destin_loc()

surf <- mc_surface(dtm, funct = "t", move = 8)
# 5-minute walking catchments around three locations
bnd <- mc_boundary(surf, origin = destin[1:3, ], limit = 5, time = "m")

bnd$boundaries     # polygons with area and perimeter
plot(bnd)

movecost documentation built on June 16, 2026, 1:06 a.m.