Here is one approach. Kind of a silly example with just one grid cell, but would work with more polygons and more points.
library(sf) library(tidyverse) # make some points data # modified example from # https://r-spatial.github.io/sf/reference/geos_binary_pred.html (pts <- st_sfc(st_point(c(.5,.5)), st_point(c(1.5, 1.5)), st_point(c(2.5, 2.5))) |> st_as_sf()|> rowid_to_column(var = 'pts_id')) (pol <- st_polygon(list(rbind(c(0,0), c(2,0), c(2,2), c(0,2), c(0,0)))) |> st_sfc() |> st_as_sf()|> rowid_to_column(var = 'pol_id') ) # look at the data, crude 'map' plot(pts); plot(pol, add = TRUE) # take a look # perform the intersection pts_pol_int <- pts |> st_intersection(pol) # only going to retain the overlaps (drops non-intersecting elements) # count the overlaps cont_pts_pol_int <- pts_pol_int |> st_drop_geometry() |> # pulls out the data frame (or tibble) group_by(pol_id) |> count() cont_pts_pol_int # could be joined back to pol HTH, DHL On Wed, Nov 22, 2023 at 6:39 AM MIGUEL GOMEZ DE ANTONIO <m...@ccee.ucm.es> wrote: > Dear community, > > I want to plot only the cells of a grid that contains points. > > I have a set of points (of class SpatialPointsDataFrame) and a grid (of > class SpatialPolygonDataFrame). > > I am interested in ploting the set of cells of the grid that contains > points: > > 1. Count how many points fall in each cell of the grid. > > 2. Plot only the cells that contains points. > > I tried: > > library(sf) > > Points.sf=st_as_sf(points) > > Grid.sf=st_as_sf(grid) > > A=intersects(grid.sf, points.sf) > > apply(A,1,any) > > There I get the cells that contains points but: > > 1. How can I count how many points fall in each cell > > 2. How could I plot the set of cells that contains points? > > > Thank you very much for your help, > > > Miguel Gómez de Antonio > Profesor Titular de Universidad > Dpto. Economía Aplicada, Pública y Política > Universidad Complutense de Madrid > > [[alternative HTML version deleted]] > > _______________________________________________ > 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
