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")
::install_github("LandSciTech/roads") devtools
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
<- prepExData(demoScen)
demoScen <- demoScen[[1]]
scen
<- projectRoads(landings = scen$landings.points,
prRoads weightRaster = scen$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
https://www.apache.org/licenses/LICENSE-2.0
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