convert point to a grid in R

Question

I have a latitude and longitude

locs <- structure(list(Latitude = 0.176094639, Longitude = 117.4955225), row.names = 1L, class = "data.frame")

I want to convert this into a square polygon grid with dimension of 5 km X 5 km and save the shapefile. I can't seem to find a function in R to do this and wondering if anyone has done similar work?

Answer 1

Assuming that the point you provided is the center of the grid you want,

• make the point an sf object
• buffer it by 2.5km
• get the bounding box of the buffer
• make a grid (10x10 used below)
• write the shapefile(commented out)

library(sf)
library(tidyverse) # pipe & plotting

locs <- structure(list(Latitude = 0.176094639, Longitude = 117.4955225), row.names = 1L, class = "data.frame")

# Make the point an sf object
locs_sf <- locs %>%
  st_as_sf(coords = c('Longitude', 'Latitude')) %>% 
  st_set_crs(4326)

# get the bounding box of a 2500m buffered circle around the point
box <- st_buffer(locs_sf, 2500) %>%
  st_bbox() %>%
  st_as_sfc()

# make a 10x10 grid of the bounding box
grid <- st_make_grid(box, n = c(10,10))

# Use st_write() to write your shapefile
#st_write(grid, '/path/to/file.shp')

ggplot() +
  geom_sf(data = locs_sf, color = 'red', size = 5) + 
  geom_sf(data = grid, fill = NA, color = 'black')

^{Created on 2022-03-24 by the reprex package (v2.0.1)}