How can I draw Crow Tessellation polygons instead of segments?

Question

I found a method for drawing Voronoi tessellation segments using ggplot2:

library(deldir) library(ggplot2) library(ggthemes) set.seed(123) df <- data.frame(lat = rnorm(20,39,10),long = rnorm(20,-98,15)) voronoi <- deldir(df$long, df$lat) ggplot(data=df, aes(x=long,y=lat)) + geom_segment(aes(x = x1, y = y1, xend = x2, yend = y2),size = 2,data = voronoi$dirsgs,linetype = 1,color= "#419AB0") + geom_point(fill="#EACA3E",pch=21,size = 4,color="white") 

I would like to know if it is possible to draw polygons on segments, but I do not know how to create a dataset with the outline of each polygon.

Answer 1

Here's an easy way to convert line segments to SpatialPolygons .

 library(rgeos) ## Convert data.frame of segment coordinates to a list of SpatialLines objects ll <- apply(voronoi$dirsgs, 1, FUN=function(X) { readWKT(sprintf("LINESTRING(%s %s, %s %s)", X[1], X[2], X[3], X[4])) }) ## Convert SpatialLines list to SpatialPolygons object pp <- gPolygonize(ll) ## Plot to check that it works set.seed=11 plot(pp, col=sample(colors(), length(pp)))