Packages and data

map <- st_union(depmunic) |> 
  st_sf() |> 
  nngeo::st_remove_holes()
map

## Simple feature collection with 1 feature and 0 fields
## Geometry type: POLYGON
## Dimension:     XY
## Bounding box:  xmin: 472365.2 ymin: 4199888 xmax: 481469.4 ymax: 4209186
## Projected CRS: GGRS87 / Greek Grid
##                         geometry
## 1 POLYGON ((477903 4202529, 4...