Create a matrix showing which planning units are spatially connected to each other.

connected_matrix(x, ...)

# S3 method for Raster
connected_matrix(x, directions = 4L, ...)

# S3 method for SpatialPolygons
connected_matrix(x, ...)

# S3 method for SpatialLines
connected_matrix(x, ...)

# S3 method for SpatialPoints
connected_matrix(x, distance, ...)

# S3 method for default
connected_matrix(x, ...)

Arguments

x Raster-class or Spatial-class object. Note that if x is a Raster-class object then it must have only one layer. not used. integer If x is a Raster-class object, the number of directions in which cells should be connected: 4 (rook's case), 8 (queen's case), 16 (knight and one-cell queen moves), or "bishop" to connect cells with one-cell diagonal moves. numeric If x is a SpatialPoints-class object, the distance that planning units have to be within in order to qualify as being connected.

Value

dsCMatrix-class object.

Details

This function returns a dgCMatrix-class sparse matrix. Cells along the off-diagonal indicate if two planning units are connected. Cells along the diagonal are zero to reduce memory consumption. Note that for Raster-class arguments to x, pixels with NA have zeros in the returned object to reduce memory consumption and be consistent with boundary_matrix, and connectivity_matrix.

Examples

# load data
data(sim_pu_raster, sim_pu_polygons, sim_pu_lines, sim_pu_points)

# create connected matrix using raster data
## crop raster to 9 cells
r <- crop(sim_pu_raster, c(0, 0.3, 0, 0.3))

## make connected matrix
cm_raster <- connected_matrix(r)

# create connected matrix using polygon data
## subset 9 polygons
ply <- sim_pu_polygons[c(1:2, 10:12, 20:22), ]

## make connected matrix
cm_ply <- connected_matrix(ply)

# create connected matrix using polygon line
## subset 9 lines
lns <- sim_pu_lines[c(1:2, 10:12, 20:22), ]

## make connected matrix
cm_lns <- connected_matrix(lns)

## create connected matrix using point data
## subset 9 points
pts <- sim_pu_points[c(1:2, 10:12, 20:22), ]

# make connected matrix
cm_pts <- connected_matrix(pts, distance = 0.1)

# plot data and the connected matrices
par(mfrow = c(4,2))

## plot raster and connected matrix
plot(r, main = "raster", axes = FALSE, box = FALSE)
plot(raster(as.matrix(cm_raster)), main = "connected matrix", axes = FALSE,
box = FALSE)

## plot polygons and connected matrix
plot(r, main = "polygons", axes = FALSE, box = FALSE)
plot(raster(as.matrix(cm_ply)), main = "connected matrix", axes = FALSE,
box = FALSE)

## plot lines and connected matrix
plot(r, main = "lines", axes = FALSE, box = FALSE)
plot(raster(as.matrix(cm_lns)), main = "connected matrix", axes = FALSE,
box = FALSE)

## plot points and connected matrix
plot(r, main = "points", axes = FALSE, box = FALSE)
plot(raster(as.matrix(cm_pts)), main = "connected matrix", axes = FALSE,
box = FALSE)