Manuel, I think you're looking for an intersect*s* rather than the intersection. Is the following what you're after?
nc = st_read(system.file("shape/nc.shp", package="sf")) nc <- st_transform(nc, 3857) g_50000 <- st_make_grid(nc, cellsize = 50000) |> st_as_sf() g_50000 <- g_50000[nc, ] g_50000_d <- st_union(g_50000) g_25000 = st_make_grid(g_50000_d, cellsize = 25000) |> st_as_sf() g_25000 # Geometry type: POLYGON index <- which(lengths(st_intersects(g_50000, nc)) > 0) plot(st_union(g_50000[index,])) On Fri, Feb 10, 2023 at 12:53 PM Bede-Fazekas Ákos <bfalevl...@gmail.com> wrote: > Dear Manuel, > > technically, the result of st_intersection(x, y), where both x and y are > POLYGONs, can be POINT, LINESTRING, POLGYON and GEOMETRY as well. The > result is GEOMETRY if the type of the different features is not the same > (e.g. POLYGON+POINT). > You can subset the result in this way: > g_25000_c_polygons_only <- g_25000_c[st_is(x = g_25000_c, type = > "POLYGON")] > > HTH, > Ákos > ___________ > Ákos Bede-Fazekas > Centre for Ecological Research, Hungary > > 2023.02.10. 18:32 keltezéssel, Manuel Spínola írta: > > Dear list members, > > > > I am trying to "crop" a polygon (grid) with a polygon, but the result is > an > > sf object Geometry type: GEOMETRY, instead of an sf object Geometry type: > > POLYGON. > > > > How can I obtain an sf POLYGON? > > > > nc = st_read(system.file("shape/nc.shp", package="sf")) > > > > > > > > nc <- st_transform(nc, 3857) > > > > > > > > g_50000 <- st_make_grid(nc, cellsize = 50000) |> st_as_sf() > > > > > > > > g_50000 <- g_50000[nc, ] > > > > > > > > g_50000_d <- st_union(g_50000) > > > > > > > > g_25000 = st_make_grid(g_50000_d, cellsize = 25000) |> st_as_sf() > > > > > > > > g_25000 # Geometry type: POLYGON > > > > > > > > g_25000_c <- st_intersection(g_25000, g_50000_d) > > > > > > > > g_25000_c # Geometry type: GEOMETRY > > > > > > > > > > _______________________________________________ > R-sig-Geo mailing list > R-sig-Geo@r-project.org > https://stat.ethz.ch/mailman/listinfo/r-sig-geo > [[alternative HTML version deleted]] _______________________________________________ R-sig-Geo mailing list R-sig-Geo@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-geo