smoothr - apply to ARC

[mdsumner]

https://github.com/mstrimas/smoothr

Apply this to arcs and recompose for topological-aware smoothing

[mdsumner]

First stab

library(silicate)
library(sf)
data(wrld_simpl, package = "maptools")
w <- st_as_sf(wrld_simpl)
#x <- polymesh
x <- subset(w, NAME %in% c("Brazil", "Paraguay", "Bolivia", "Peru", "Colombia")) #rmapshaper::ms_simplify(inlandwaters[c(3, 6), ])
a <- ARC(x)



b <- a$arc_link_vertex %>% split(.$arc_) %>% 
  purrr::map(~smoothr::smooth_chaikin(dplyr::inner_join(.x, a$vertex) %>% 
                                       dplyr::select(x_, y_) %>% as.matrix(), refinements = 3, wrap = FALSE))
# b <- a$arc_link_vertex %>% split(.$arc_) %>% 
#   purrr::map(~smoothr::smooth_spline(dplyr::inner_join(.x, a$vertex) %>% 
#                                        dplyr::select(x_, y_) %>% as.matrix(), n = nrow(.x) * 4, wrap = FALSE))


op <- par(mfrow = c(2, 1), mar = rep(0, 4))
plot(x$geometry, col = NA, border = NA, asp = "")
purrr::walk(b, lines, col = "red")
plot(x$geometry, asp = "")
par(op)

[mpadge]

That is so cool!

[mdsumner]

Isn't it? It's what I thought would be easy in #45 and #60, and there's so many applications.

[mdsumner]

Try to implement Visvalingam https://bost.ocks.org/mike/simplify/ and https://gist.github.com/msbarry/9152218

[mdsumner]

Vis is done here: hypertidy/area#3