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library(duckdbfs)
library(dplyr)
library(sf)
library(spData)
duckdbfs::load_h3()
duckdbfs::load_spatial()
#fs::file_delete(tmp)
ex1 <- spData::us_states |> dplyr::filter(NAME == "Arizona")
ex2 <- world |> filter(iso_a2 == "US")
as_dataset.sf <- function(sf, ...) {
# cludgy way to get polygon into duckdb as spatial data
tmp <- tempfile(fileext = ".fgb")
sf |> st_transform(4326) |> write_sf(tmp, append = FALSE)
aoi <- open_dataset(tmp, ...)
aoi
}
get_h3index <- function(aoi, zoom = 0L, precision = 6L) {
zoom <- as.integer(zoom)
# consider auto-retry at higher precision if subset is empty.
precision <- as.integer(precision)
res <- paste0("h", precision)
# multipolygon dump may not be needed for draw tools.
h3_aoi <- aoi |>
mutate(poly = array_extract(unnest(st_dump(geom)),"geom"),
hexid = h3_polygon_wkt_to_cells(poly,{precision}),
hexid = unnest(hexid)
) |>
mutate(h0 = h3_h3_to_string( h3_cell_to_parent(hexid, {zoom})),
hexid = h3_h3_to_string (hexid) ) |>
mutate(h0 = toupper(h0), hexid = toupper(hexid))
# create a view as well
h3_aoi |> select(h0, hexid) |>
#rename(!!res := hexid) |>
as_view("h3_aoi")
subset <- h3_aoi |>
select(h0) |>
distinct() |>
pull(h0)
subset
}
aoi <- as_dataset.sf(ex1)
subset <- get_h3index(aoi)
urls <- paste0("https://minio.carlboettiger.info/public-gbif/hex/h0=", subset, "/part0.parquet")
gbif <- open_dataset(urls, tblname = "gbif")
x <- gbif |> rename(hexid = h8) |> count(hexid, name = "count")
con <- cached_connection()
y <- tbl(con, "h3_aoi")
hex_join <- function(x,y) {
res_x <- x |> head(1) |> mutate(res = h3_get_resolution(hexid)) |> pull(res)
res_y <- y |> head(1) |> mutate(res = h3_get_resolution(hexid)) |> pull(res)
if (res_x > res_y) {
y <- y |>
mutate(hexid = unnest(
h3_cell_to_children(hexid, {res_x})),
hexid = toupper(hexid)
)
}
if (res_x < res_y) {
y <- y |>
mutate(hexid = h3_cell_to_parent(hexid, {res_x}))
}
inner_join(x, y)
}
hex_join(x,y)
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