example code for working with s2 parent cells and mapping with rdeck (#…

…33)

inst/addr_and_s2.R

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+devtools::load_all()
+library(s2)
+library(dplyr, warn.conflicts = FALSE)
+
+cagis_s2 <-
+  cagis_addr()$cagis_addr_data |>
+  purrr::modify_if(\(.) length(.) > 0 && nrow(.) > 1, dplyr::slice_sample, n = 1) |>
+  purrr::map_vec(purrr::pluck, "cagis_s2", .default = NA, .ptype = s2::s2_cell())
+
+d <- addr_match_geocode(
+  x = sample(voter_addresses(), 500),
+  ref_addr = cagis_addr()$cagis_addr,
+  ref_s2 = cagis_s2,
+  county = "39061",
+  year = "2022"
+)
+
+table(d$match_method)
+
+d <- d |>
+  filter(match_method %in% c("ref_addr", "tiger_range")) |>
+  mutate(
+    s2_fine_grid = s2_cell_parent(s2, 14),
+    s2_coarse_grid = s2_cell_parent(s2, 13),
+    across(c(s2_fine_grid, s2_coarse_grid), as.character, .names = "{.col}_char")
+  )
+
+# median cell side length in m
+sqrt(median(s2_cell_area_approx(d$s2_fine_grid)))
+# median area in sq km
+median(s2_cell_area_approx(d$s2_fine_grid)) / 1000000
+
+sqrt(median(s2_cell_area_approx(d$s2_coarse_grid)))
+median(s2_cell_area_approx(d$s2_coarse_grid)) / 1000000
+
+d$geometry <- sf::st_as_sfc(s2::s2_cell_center(d$s2))
+
+bg <-
+  get_tiger_block_groups("39", "2022") |>
+  dplyr::filter(substr(GEOID, 1, 5) == "39061") |>
+  dplyr::mutate(geometry = sf::st_as_sfc(s2_geography))
+
+## s2_plot(bg$s2_geography, border = codec::codec_colors("grey blue"), col = codec::codec_colors("white"))
+## s2::s2_plot(s2_cell_to_lnglat(d$s2), add = TRUE, col = codec::codec_colors("darkish blue"), pch = 19)
+
+library(rdeck)
+
+rdeck(
+  map_style = "mapbox://styles/brokamrc/cm2jtbccr007801pebyz0hk43",
+  initial_bounds = sf::st_bbox(bg$geometry)
+) |>
+  add_polygon_layer(
+    data = bg,
+    name = "block groups",
+    get_polygon = geometry,
+    opacity = 0.7,
+    filled = FALSE,
+    stroked = TRUE,
+    get_line_color = codec::codec_colors("darkish blue"),
+    get_line_width = 20,
+    visible = TRUE,
+    visibility_toggle = TRUE,
+    pickable = FALSE
+  ) |>
+  add_s2_layer(
+    data = d,
+    name = "S2 geometry level 13 (~ 1 sq km)",
+    get_s2_token = s2_coarse_grid_char,
+    opacity = 0.2,
+    get_fill_color = codec::codec_colors("light blue")
+  ) |>
+  add_s2_layer(
+    data = d,
+    name = "S2 geometry level 14 (~ 0.25 sq km)",
+    get_s2_token = s2_fine_grid_char,
+    opacity = 0.2,
+    get_fill_color = codec::codec_colors("orange")
+  ) |>
+  add_scatterplot_layer(
+    name = "S2 geometry cell center",
+    data = d,
+    opacity = 1,
+    get_radius = 34,
+    get_position = geometry,
+    get_fill_color = codec::codec_colors("red"),
+  )