leastcostpath (version 1.8.7)

crop_cs: Crop Cost Surface

Description

Crops Cost Surfaces to the supplied SpatialPolygon* boundary

Usage

crop_cs(cost_surface, boundary)

Value

TransitionLayer (gdistance package). Cropped Cost Surface

Arguments

cost_surface

TransitionLayer (gdistance package). Cost surface to crop

boundary

Spatial* (sp package) or RasterLayer (raster package). Boundary used when cropping Cost Surface. See details for more

Author

Joseph Lewis

Details

The resultant Cost Surface is cropped to the Spatial* or RasterLayer object. All areas of the Cost Surface that are outside the supplied boundary are given a conductance value of 0. The conductance value of 0 ensures that movement is inhibited within these areas. If a RasterLayer object is supplied in the boundary argument then all cells with a value of NA will be given a Conductance value of 0.

Examples

r <- raster::raster(system.file('external/maungawhau.grd', package = 'gdistance'))

pt = cbind(2667670, 6479000)
pt = sp::SpatialPoints(pt)
polygon <- rgeos::gBuffer(spgeom = pt, width = 200)
raster::crs(pt) <- raster::crs(r)
raster::crs(polygon) <- raster::crs(r)

slope_cs <- create_slope_cs(r, cost_function = 'tobler', neighbours = 16, max_slope = NULL)

slope_cs_pt <- crop_cs(cost_surface = slope_cs, boundary = pt)
slope_cs_polygon <- crop_cs(cost_surface = slope_cs, boundary = polygon)

r2 <- r
ext <- raster::extent(2667500, 2667900, 6478800, 6479500)
cells <- unlist(raster::cellFromPolygon(object = r, p = as(ext, 'SpatialPolygons')))
r2[-cells] <- NA

slope_cs_raster <- crop_cs(cost_surface = slope_cs, boundary = r2)