The roads package offers iterative least cost path and minimum spanning
tree methods for projecting forest road networks. The methods connect a
set of target points to an existing road network using igraph
https://igraph.org to identify least cost routes. The cost of
constructing a road segment between adjacent pixels is determined by a
user supplied weightRaster and a weightFunction; options include the
average of adjacent weightRaster values, and a function of the
elevation differences between adjacent cells that penalizes steep
grades. These road network projection methods are intended for
integration into R workflows and modelling frameworks used for
forecasting forest change, and can be applied over multiple timesteps
without rebuilding a graph at each timestep.
You can install the released version of roads from CRAN with:
install.packages("roads")And the development version from GitHub with:
# install.packages("devtools")
devtools::install_github("LandSciTech/roads")To simulate the development of roads three inputs are needed: the
current road network, the locations that should be connected to the road
network (landings), and a weights raster that together with the
weighting function determines the cost to connect two raster cells with
a road. Typically the roads and landings are sf objects or sp
Spatial* objects and the weight is a raster.
library(roads)
library(raster)
# data set installed with roads package
demoScen <- prepExData(demoScen)
scen <- demoScen[[1]]
prRoads <- projectRoads(landings = scen$landings.points,
weightRaster = scen$cost.rast,
roads = scen$road.line,
plotRoads = TRUE) 
By default projectRoads uses an iterative least cost paths algorithm
(roadMethod = "ilcp") to connect each landing to the existing road by
the lowest cost path, updating the cost after each landing is connected.
A minimum spanning tree method (roadMethod = "mst") is also available.
For more details see vignette("roads-vignette", package = "roads")
Copyright (C) 2021 Her Majesty the Queen in Right of Canada, as represented by the Minister of Environment and Climate Change.
And
Copyright 2018 Province of British Columbia
Licensed under the Apache License, Version 2.0 (the “License”); you may not use this file except in compliance with the License. You may obtain a copy of the License at
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