How to build polygons from buffered points and merge overlapping ones using R?

Question

I have a sample of 3 groups of points which are similarly spread within their groups.

> pts
             x        y
 [1,] 453067.5 364073.5
 [2,] 453066.5 364072.5
 [3,] 453068.5 364072.5
 [4,] 453063.5 364071.5
 [5,] 453065.5 364071.5
 [6,] 453067.5 364071.5
 [7,] 453069.5 364071.5
 [8,] 453071.5 364071.5
 [9,] 453062.5 364070.5
[10,] 453064.5 364070.5
[11,] 453067.5 364065.5
[12,] 453069.5 364065.5
[13,] 453071.5 364065.5
[14,] 453073.5 364065.5
[15,] 453075.5 364065.5
[16,] 453077.5 364065.5
[17,] 453079.5 364065.5
[18,] 453054.5 364064.5
[19,] 453056.5 364064.5
[20,] 453058.5 364064.5

Then I can convert to sp object: pts_sf = sf::st_as_sf(as.data.frame(pts), coords = c(1,2)). Now trying to create buffer pts_buf <- gBuffer(pts_sf, TRUE, 2) but get error

Error in (function (classes, fdef, mtable) : unable to find an inherited method for function ‘is.projected’ for signature ‘"sf"’

Other way round, I can use buffer like this pts_buf <- sf::st_buffer(pts_sf, 2) but now I get error when trying pts_uni <- rgeos::gIntersects(pts_buf, byid=TRUE, returnDense = FALSE)

Error in RGEOSBinPredFunc(spgeom1, spgeom2, byid, func) :
rgeos_convert_R2geos: invalid R class, unable to convert

I use pts_int = sf::st_intersects(pts_buf) but this is not an object I need. Can I find any compatibilities to go out with it?

Answer 1

Found a solution using sf package:

So having a matrix of points, First I need sf object

pts_sf = sf::st_as_sf(as.data.frame(pts), coords = c(1,2))

Next I can perform buffer

pts_buf <- sf::st_buffer(pts_sf, 2)

then union

pts_com <- sf::st_union(pts_buf)

and ath end I can get normal polygon from it

pts_pol <- sf::st_cast(pts_com, "POLYGON")

This works well for larger data as well. Tested for up to 1M of points.