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As I understand it R lacks a methods to buffer polygons in a spatially exclusive way that preserves the topology of adjacent polygons. So I'm experimenting with an approach that generates voronoi polygons of the original polygon vertices. Results seem quite promising except for apparent errors in the voronoi generation.
This is a minimal code version:
require(rworldmap)
require(rgeos)
require(dismo)
require(purrr)
require(dplyr)
par(mai = rep(0,4))
p = rworldmap::countriesCoarse[,'ADMIN']
p = p[p$ADMIN %in% c('United States of America', 'Canada'),]
p$ADMIN = as.character(p$ADMIN)
p = rgeos::gBuffer(p, byid=T, width = 0) # precaution to ensure no badly-formed polygon nonsense
p_buff2 = rgeos::gBuffer(p, byid=T, width = -.00002) # order of 1 metre
vertices2 = map_df(p_buff2@polygons, ~ map2_df(.x@Polygons, rep(.x@ID, length(.x@Polygons)),
~ as.data.frame(..1@coords) %>% `names<-`(c('x','y')) %>% mutate(id = ..2)))
coordinates(vertices2) = vertices2[,1:2]
vor2 = dismo::voronoi(vertices2)
plot(p_buff2)
plot(vertices2, add=T, pch=16, cex=.4, col = c('red','blue')[factor(vertices2$id)])
plot(vor2, add=T, border='#00000010', col = c('#FF000040','#0000FF40')[factor(vor2$id)])
Note the misclassified buts of British Colombia and Alaska.
The text was updated successfully, but these errors were encountered:
This question has full details https://stackoverflow.com/questions/62735729/voronoi-errors-with-dismovoronoi
As I understand it R lacks a methods to buffer polygons in a spatially exclusive way that preserves the topology of adjacent polygons. So I'm experimenting with an approach that generates voronoi polygons of the original polygon vertices. Results seem quite promising except for apparent errors in the voronoi generation.
This is a minimal code version:
Note the misclassified buts of British Colombia and Alaska.
The text was updated successfully, but these errors were encountered: