R/keepOutline.R

In paul-carteron/cadastreAnalysis: Analysis of cadastral parcels in France

#' keepOutline
#'
#' @param parcelles L'objet sf contenant les parcelles
#'
#' @return Le contour de nos parcelles. Format sortie : Lambert93 / EPSG : 2154
#' @export
#'
#' @importFrom rmapshaper ms_simplify
#' @importFrom nngeo st_remove_holes
#' @importFrom sf st_make_valid st_sf st_transform st_union
#'
#'
keepOutline <- function(parcelles) {

   coordSys = st_crs(parcelles)

   if (dim(parcelles)[1] == 1){
      return(parcelles)
   }

   res = parcelles %>%
      st_transform(2154) %>%
      ms_simplify(keep_shapes = 1, snap_interval = 20) %>%
      st_union() %>%
      st_remove_holes() %>%
      st_make_valid() %>%
      st_sf() %>%
      st_transform(coordSys)

   return(res)
}