Cause of warning when trying to simplify polygons?

Question

I've got a leaflet map and I'm plotting some polygons on top of it. I'm trying to use rmapshaper::ms_simplify() to decrease the loading time for the map.

    polygons_ll <- (
      spTransform(polygons, CRS("+proj=longlat +datum=WGS84"))
    )

    polygons_ll <- ms_simplify(polygons_ll)

This is all within a R shiny application, which doesn't run after encountering the warning:

Warning in sp::proj4string(sp) :
  CRS object has comment, which is lost in output

The app was functioning before the addition of the ms_simplify().

Answer 1

After doing some research and trial and error:

rgdal::set_rgdal_show_exportToProj4_warnings(FALSE)

will suppress the warning.

I ended up using:

crs <- CRS("+proj=longlat +datum=WGS84")

polygons_ll <- polygons %>% 
    rgeos::gSimplify(tol=25, topologyPreserve=TRUE) %>% 
    spTransform(crs)

# overwrite untransformed polygons with transformed polygons
polygons@polygons <- polygons@polygons

Maps are much faster to load now.