Convert Shapefile to H3 - R

Question

I have a gpkg file which contains some buildings and am looking to convert this to H3 size 11.

BUILDINGS <- st_read(GPKG, layer = "buildings")

Basically anywhere one of these buildings is located gets a hexagon, and where there aren't any buildings there is no hexagon.

I tried using some packages i.e. "h3jsr" and "h3"

and also tried

install.packages("remotes")
remotes::install_github("crazycapivara/h3forr")

hoping to use the "geo_to_h3" function, but it just says it cannot find the function at all so not sure whats happening there.

Any help would be greatly appreciated!

Update

So not each individual building is a polygon but a collection of buildings are grouped into one polygon.

Do these packages support `latlng_to_cell`? That's the H3v4 name for this function — nrabinowitz, Feb 27 '23 at 17:58
Assuming you solve the technical issue here, you have two options - `latlng_to_cell` would require the centroid of the building and output a single cell, or `polygon_to_cells` would require the building polygon and output a set of cells — nrabinowitz, Feb 27 '23 at 18:00

score 0 · Accepted Answer · answered Mar 08 '23 at 11:18

Found the answer - Some buildings did not cross the centre point of the H3 cells at size 11, which caused an error. This was fixed by reducing the size of the cells and then finding the parent cells.

FINAL_CELLS <- data.frame()
for(i in 1:nrow(BUILDING)){
  # Subset each Polygon
  SUB_BUILDING <- st_transform(BUILDING[i,], crs = 4326)
  
  # Convert polygon to H3 cells (must be higher resolution to avoid issues)
  CELLS <- polygon_to_cells(SUB_BUILDING, res = 14, simple = FALSE)
  
  # Get parent H3 cells from child H3 cells (This is final resolution)
  P <- get_parent(unlist(CELLS$h3_addresses), res = 11, simple = T)
  
  # Remove duplicate H3 cells
  P <- data.frame(id = SUB_BUILDING$id, cell =  unique(P))
  
  FINAL_CELLS <- rbind(P,FINAL_CELLS)
  
  print(paste(i,"-",Sys.time()))
}

Convert Shapefile to H3 - R

1 Answers1