RDocumentation: shortestPath

Note that this notebook was automatically generated from an RDocumentation page. It depends on the package and the example code whether this code will run without errors. You may need to edit the code to make things work.

if(!require('gdistance')) {
    install.packages('gdistance')
    library('gdistance')
}

#example equivalent to that in the documentation on r.cost/r.drain in GRASS
r <- raster(nrows=6, ncols=7, xmn=0, xmx=7, ymn=0, ymx=6, crs="+proj=utm +units=m")

r[] <- c(2, 2, 1, 1, 5, 5, 5,
         2, 2, 8, 8, 5, 2, 1,
         7, 1, 1, 8, 2, 2, 2,
         8, 7, 8, 8, 8, 8, 5,
         8, 8, 1, 1, 5, 3, 9,
         8, 1, 1, 2, 5, 3, 9)

tr <- transition(r, function(x) 1/mean(x), 8) 
# 1/mean: reciprocal to get permeability
tr <- geoCorrection(tr)

c1 <- c(5.5,1.5) 
c2 <- c(1.5,5.5)

#make a SpatialLines object for visualization
sPath1 <- shortestPath(tr, c1, c2, output="SpatialLines")
plot(r)
lines(sPath1)

#make a TransitionLayer for further calculations
sPath2 <- shortestPath(tr, c1, c2)

plot(raster(sPath2))