boundary_matrix: Boundary matrix

In prioritizr/prioritizrutils: Utilities for prioritizr

Description

Generate a boundary matrix describing the shared and exposed edges of planning units.

Usage

boundary_matrix(x, ...)

## S3 method for class 'Raster'
boundary_matrix(x, ...)

## S3 method for class 'SpatialPolygons'
boundary_matrix(x, ...)

## S3 method for class 'SpatialLines'
boundary_matrix(x, ...)

## S3 method for class 'SpatialPoints'
boundary_matrix(x, ...)

## S3 method for class 'data.frame'
boundary_matrix(x, ...)

Arguments

x	Raster-class, SpatialLines-class, or SpatialPolygons-class object. If x is a Raster-class object then it must have only one layer.
...	not used.

Details

This function returns a dsCMatrix-class symmetric sparse matrix. Cells on the off-diagonal indicate the length of the shared boundary between two different planning units. Cells on the diagonal indicate length of a given planning unit"s edges that have no neighbors (eg. for edges of planning units found along the coastline). This function assumes the data are in a coordinate system where Euclidean distances accurately describe the proximity between two points on the earth. Thus spatial data in a longitude/latitude coordinate system (aka WGS84) should be reprojected to another coordinate system before using this function.

Value

Matrix{dsCMatrix-class} object.

Examples

## load data
data(sim_pu_raster, sim_pu_polygons)

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

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

# plot raster and connected matrix
par(mfrow=c(1, 2))
plot(r, main = "raster")
plot(raster(as.matrix(bm_raster)), main = "boundary matrix")

# plot polygons and connected matrix
par(mfrow=c(1, 2))
plot(r, main = "polygons")
plot(raster(as.matrix(bm_ply)), main = "boundary matrix")

prioritizr/prioritizrutils documentation built on May 25, 2019, 12:20 p.m.