Spatial Joins

This lesson is called Spatial Joins, part of the Mapping with R course. This lesson is called Spatial Joins, part of the Mapping with R course.

Transcript

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View code shown in video

library(tidyverse)
library(janitor)
library(sf)
library(scales)

improved_corners <-
  read_sf("https://raw.githubusercontent.com/rfortherestofus/mapping-with-r-v2/refs/heads/main/data/improved_corners.geojson")

improved_corners

city_council_districts <-
  read_sf("https://raw.githubusercontent.com/rfortherestofus/mapping-with-r-v2/refs/heads/main/data/portland_city_council_districts.geojson")

city_council_districts

st_join(
  city_council_districts,
  improved_corners
)

unimproved_corners_by_districts <-
  st_join(
    improved_corners,
    city_council_districts
  ) |>
  filter(ramp_style == "Unimproved")

portland_boundaries <-
  read_sf("https://raw.githubusercontent.com/rfortherestofus/mapping-with-r-v2/refs/heads/main/data/portland_boundaries.geojson")

ggplot() +
  geom_sf(data = portland_boundaries, color = "transparent") +
  geom_sf(data = unimproved_corners_by_districts) +
  theme_void() +
  facet_wrap(vars(district))

improved_corners_by_district <-
  st_join(
    city_council_districts,
    improved_corners
  ) |>
  st_drop_geometry() |>
  count(district, ramp_style) |>
  drop_na(district) |>
  group_by(district) |>
  mutate(pct = n / sum(n)) |>
  ungroup() |>
  left_join(city_council_districts, join_by(district)) |>
  st_as_sf()

improved_corners_by_district |>
  filter(ramp_style == "Improved") |>
  ggplot() +
  geom_sf(aes(fill = pct)) +
  geom_sf_text(
    data = city_council_districts,
    aes(label = district),
    color = "white"
  ) +
  labs(fill = NULL) +
  scale_fill_viridis_c(
    option = "B",
    limits = c(0.25, 0.35),
    labels = percent_format(accuracy = 1)
  ) +
  theme_void() +
  theme(
    legend.position = "top",
    legend.key.width = unit(2, "cm"),
    legend.key.height = unit(0.5, "cm")
  )

Your Turn

Import data on Portland sextants using this code:

library(sf)

portland_sextants <-
  read_sf(
    "https://raw.githubusercontent.com/rfortherestofus/mapping-with-r-v2/refs/heads/main/data/portland_sextants.geojson"
  )

Import data on Portland traffic signals using this code:

portland_traffic_signals <-
  read_sf(
    "https://raw.githubusercontent.com/rfortherestofus/mapping-with-r-v2/refs/heads/main/data/portland_traffic_signals.geojson"
  )