@TakahiroShimada plotKML has not been updated to remove dependency on rgdal or maptools by the 16 October deadline https://github.com/Envirometrix/plotKML/issues/14. Because SDLfilter imports plotKML, it will also fail when plotKML gets archived (17-18 October). Pleae try to move plotKML to suggests and condition on all use (code, vignettes, examples, demos, etc.). See https://r-spatial.github.io/evolution/ for details.
@TakahiroShimada plotKML has not been updated to remove dependency on rgdal or maptools by the 16 October deadline https://github.com/Envirometrix/plotKML/issues/14. Because SDLfilter imports plotKML, it will also fail when plotKML gets archived (17-18 October). Pleae try to move plotKML to suggests and condition on all use (code, vignettes, examples, demos, etc.). See https://r-spatial.github.io/evolution/ for details.