Remove or extract holes from polygons, or fill holes in raster data

Remove the holes in SpatVector polygons. If inverse=TRUE the holes are returned (as polygons).

Or remove "holes" in SpatRasters.

Usage

# S4 method for class 'SpatVector'
fillHoles(x, inverse=FALSE)

# S4 method for class 'SpatRaster'
fillHoles(x, nearest=FALSE)

Arguments

x

SpatVector

inverse

logical. If TRUE the holes are returned as polygons

nearest

logical. If FALSE only holes that are surrounded by cells with the same value are filled. Otherwise, the values of the nearest cell that is not NA is assigned

Value

SpatVector

See also

snap, gaps

Examples

x <- rbind(c(50,0), c(140,60), c(160,0), c(140,-55))
hole <- rbind(c(80,0), c(105,13), c(120,2), c(105,-13))

z <- rbind(cbind(object=1, part=1, x, hole=0), 
       cbind(object=1, part=1, hole, hole=1))
colnames(z)[3:4] <- c('x', 'y')
p <- vect(z, "polygons", atts=data.frame(id=1), crs="local")
p
#>  class       : SpatVector 
#>  geometry    : polygons 
#>  dimensions  : 1, 1  (geometries, attributes)
#>  extent      : 50, 160, -55, 60  (xmin, xmax, ymin, ymax)
#>  coord. ref. : Cartesian (Meter) 
#>  names       :    id
#>  type        : <num>
#>  values      :     1

f <- fillHoles(p)
g <- fillHoles(p, inverse=TRUE)

plot(p, lwd=16, border="gray", col="light yellow")
polys(f, border="blue", lwd=3, density=4, col="orange")
polys(g, col="white", lwd=3)



## SpatRaster
v <- vect(c("POLYGON ((81.572 36.629, 98.508 9.624, 80 0, 99.902 -10.349, 
  84.662 -34.709, 50 0, 81.572 36.629))", "POLYGON ((140 60, 160 0, 
  140 -55, 84.662 -34.709, 99.902 -10.349, 105 -13, 120 2, 105 13, 
  98.508 9.624, 81.572 36.629, 140 60))"))
v <- rbind(v, shift(p ,-120))
v$ID <- 1:nrow(v)
r <- rasterize(v, rast(xmin=-80, crs="local"), "ID")

f1 <- fillHoles(r)
f2 <- fillHoles(r, nearest=TRUE)