Shortest Paths Between Points in Grids.
The package computes shortest paths between points in grids. It can take barriers and custom transition functions into account. Apart from applications regarding planet Earth, spaths can compute shortest paths generally on spheres and planes. The package is optimized for computational performance, customizability, and user friendliness. It comes with its own graph-theoretical implementation tailored to gridded data.
Install the package via devtools::install_github("cdueben/spaths", build_vignettes = T) and consult the vignette with vignette("spaths_introduction", "spaths") for an introduction.
Extensions to this package are certainly welcome. You can either suggest modifications to spaths by sending me an email or submitting a pull request, or you can build a package that calls spaths.