A wrapper around the C++ library 'polylabel' from 'Mapbox', providing an efficient routine for finding the approximate pole of inaccessibility of a polygon, which usually serves as an excellent candidate for labeling of a polygon.
polylabelr is an R wrapper for the polylabel
Mapbox. It currently contains a single
poi() that finds the pole of inaccessibility of a polygon,
which usually makes for a good place to put a label on a polygon—hence
# a concave polygonx <- c(0, 4, 1, 6, 7, 7, 0, 0)y <- c(0, 0, 1, 2, 1, 3, 2, 0)# locate the pole of inaccessibilityp <- polylabelr::poi(x, y, precision = 0.01)plot.new()plot.window(range(x, na.rm = TRUE), range(y, na.rm = TRUE))polypath(x, y, col = "grey", border = FALSE)points(p)
The source code from polylabel and geometry.hpp has been modified in a few ways to compile properly with c++11 using the standard flags required by CRAN policies. polylabel has also been modified to return the distance from the chosen point to the enclosing polygon, in case it is of value to users.