Libraries

library(tidyverse)
library(sf)
library(units)
library(ggrepel)
library(gghighlight)
library(USAboundaries)
library(rnaturalearth)
library(knitr)

Question 1

#USAboundaries data

eqdc = '+proj=eqdc +lat_0=40 +lon_0=-96 +lat_1=20 +lat_2=60 +x_0=0 +y_0=0 +datum=NAD83 +units=m +no_defs'

conus = USAboundaries::us_states(resolution = "low") %>%
  filter(!name %in% c("Alaska", "Puerto Rico", "Hawaii"))

conus = st_transform(conus, '+proj=eqdc +lat_0=40 +lon_0=-96 +lat_1=20 +lat_2=60 +x_0=0 +y_0=0 +datum=NAD83 +units=m +no_defs')

#Country Boundaries

country_boundaries = rnaturalearth::countries110 %>%
  st_as_sf(coords = c("X", "Y"), crs = 5070 ) %>%
  filter(name %in% c("Mexico", "Canada"))

country_boundaries = st_transform(country_boundaries, '+proj=eqdc +lat_0=40 +lon_0=-96 +lat_1=20 +lat_2=60 +x_0=0 +y_0=0 +datum=NAD83 +units=m +no_defs')

#US Cities

us_cities = readr::read_csv("/Users/Noblex/github/geog-176A-labs/data/uscities.csv") %>%
  st_as_sf(coords = c("lng", "lat"), crs = 4326) %>%
  filter(!state_id %in% c("AK", "PR", "HI"))

us_cities = st_transform(us_cities, '+proj=eqdc +lat_0=40 +lon_0=-96 +lat_1=20 +lat_2=60 +x_0=0 +y_0=0 +datum=NAD83 +units=m +no_defs')

Question 2

#2.1 - 5 cities furthest from US border

conus_string = st_union(conus) %>%
  st_cast("MULTILINESTRING")

us_cities = us_cities %>%
  mutate(dist_to_border = st_distance(us_cities, conus_string),
         dist_to_border = units::set_units(dist_to_border, "km"),
         dist_to_border = units::drop_units(dist_to_border))

furthest_cities_from_border = us_cities %>%
  slice_max(dist_to_border, n = 5) %>%
  select(city, state_name, dist_to_border) %>%
  st_drop_geometry()

kable(furthest_cities_from_border, caption = "Furthest Cities from American Border (Km)",
      col.names = c("City", "State", "Distance to Border"),
      format.args = list(big.mark = ","))

Furthest Cities from American Border (Km)
City	State	Distance to Border
Dresden	Kansas	1,012.317
Herndon	Kansas	1,007.750
Hill City	Kansas	1,005.147
Atwood	Kansas	1,004.734
Jennings	Kansas	1,003.646

#2.2 - 5 furthest cities from state borders

conus_string2 = st_combine(conus) %>%
  st_cast("MULTILINESTRING")

us_cities = us_cities %>%
  mutate(dist_to_state = st_distance(us_cities, conus_string2),
         dist_to_state = units::set_units(dist_to_state, "km"),
         dist_to_state = units::drop_units(dist_to_state))

furthest_cities_from_state = us_cities %>%
  slice_max(dist_to_state, n = 5) %>%
  select(city, state_name, dist_to_state) %>%
  st_drop_geometry()

kable(furthest_cities_from_state, caption = "Furthest Cities from State Border (Km)",
      col.names = c("City", "State", "Distance to Closest State Border"),
      format.args = list(big.mark = ","))

Furthest Cities from State Border (Km)
City	State	Distance to Closest State Border
Lampasas	Texas	308.9216
Bertram	Texas	302.8190
Kempner	Texas	302.5912
Harker Heights	Texas	298.8125
Florence	Texas	298.6804

#2.3 - 5 furthest cities from Mexico

Mexico_boundary = country_boundaries %>%
  filter(name == "Mexico")

us_cities = us_cities %>%
  mutate(dist_to_mexico = st_distance(us_cities, Mexico_boundary),
         dist_to_mexico = units::set_units(dist_to_mexico, "km"),
         dist_to_mexico = units::drop_units(dist_to_mexico))

furthest_cities_from_mexico = us_cities %>%
  slice_max(dist_to_mexico, n = 5) %>%
  select(city, state_name, dist_to_mexico) %>%
  st_drop_geometry()

kable(furthest_cities_from_mexico, caption = "Furthest Cities from Mexican Border (Km)",
      col.names = c("City", "State", "Distance to Mexican Border"),
      format.args = list(big.mark = ","))

Furthest Cities from Mexican Border (Km)
City	State	Distance to Mexican Border
Caribou	Maine	3,250.334
Presque Isle	Maine	3,234.570
Calais	Maine	3,134.348
Eastport	Maine	3,125.624
Old Town	Maine	3,048.366

#2.4 - 5 furthest cities from Canada

Canada_boundary = country_boundaries %>%
  filter(name == "Canada")

us_cities = us_cities %>%
  mutate(dist_to_canada = st_distance(us_cities, Canada_boundary),
         dist_to_canada = units::set_units(dist_to_canada, "km"),
         dist_to_canada = units::drop_units(dist_to_canada))

furthest_cities_from_canada = us_cities %>%
  slice_max(dist_to_canada, n = 5) %>%
  select(city, state_name, dist_to_canada) %>%
  st_drop_geometry()

kable(furthest_cities_from_canada, caption = "Furthest Cities from Canadian Border (Km)",
      col.names = c("City", "State", "Distance to Canadian Border"),
      format.args = list(big.mark = ","))

Furthest Cities from Canadian Border (Km)
City	State	Distance to Canadian Border
Guadalupe Guerra	Texas	2,206.455
Sandoval	Texas	2,205.641
Fronton	Texas	2,204.784
Fronton Ranchettes	Texas	2,202.118
Evergreen	Texas	2,202.020

Question 3

#3.1 - Map of 10 most populated cities in US

biggest_cities = us_cities %>%
  slice_max(population, n = 10)

ggplot()+
  geom_sf(data = country_boundaries) +
  geom_sf(data = conus_string2) +
  geom_sf(data = biggest_cities, col = "red", size = 1.5) +
  ggthemes::theme_map() +
  labs(title = paste("10 Most Populated Cities in America")) +
  ggrepel::geom_label_repel(
      data = biggest_cities,
      aes(label = city, geometry = geometry),
      stat = "sf_coordinates",
      size = 2
    )

#3.2 - Map of city distances from the US border w/ 5 furthest cities

furthest_cities_from_border_w_geometry = us_cities %>%
  slice_max(dist_to_border, n = 5) %>%
  select(city, state_name, dist_to_border)

ggplot() +
  geom_sf(data = us_cities, aes(col = dist_to_border), size = .1) +
  geom_sf(data = furthest_cities_from_border_w_geometry, col = "darkblue") +
  geom_sf(data = conus_string) +
  scale_color_gradient(low = "pink", high = "darkred") +
  ggthemes::theme_map() +
  labs(title = paste("City Distances from Country Border w/ Five Furthest Cities")) +
  ggrepel::geom_label_repel(
    data = furthest_cities_from_border_w_geometry,
    aes(label = city, geometry = geometry),
    stat = "sf_coordinates",
    size = 4
  )

#3.3 - Map of city distances from state borders w/ five furthest cities

furthest_cities_from_state_w_geometry = us_cities %>%
  slice_max(dist_to_state, n = 5) %>%
  select(city, state_name, dist_to_state)

ggplot() +
  geom_sf(data = us_cities, aes(col = dist_to_state), size = .1) +
  geom_sf(data = furthest_cities_from_state_w_geometry, col = "red") +
  geom_sf(data = conus_string2) +
  scale_color_gradient(low = "lightblue", high = "navy") +
  ggthemes::theme_map() +
  labs(title = paste("City Distances from State Borders w/ Five Furthest Cities")) +
  ggrepel::geom_label_repel(
    data = furthest_cities_from_state_w_geometry,
    aes(label = city, geometry = geometry),
    stat = "sf_coordinates",
    size = 4
  )

#3.4 - cities equal distance from Canadian & Mexican borders w/ 5 most populous cities in the group

us_cities = us_cities %>%
  mutate(distance_can_mex = abs(dist_to_canada - dist_to_mexico))

equadist_can_mex = us_cities %>%
  filter(distance_can_mex < 100)

biggest_equadist_can_mex = equadist_can_mex %>%
  slice_max(population, n = 5)

ggplot() +
  geom_sf(data = country_boundaries) +
  geom_sf(data = conus_string) +
  geom_sf(data = equadist_can_mex, color = "blue", size = .1) +
  geom_sf(data = biggest_equadist_can_mex, color = "red", size = 3) +
  ggthemes::theme_map() +
  labs(title = paste("Cities equal distance from Canadian & Mexican borders")) +
  ggrepel::geom_label_repel(
    data = biggest_equadist_can_mex,
    aes(label = city, geometry = geometry),
    stat = "sf_coordinates",
    size = 3
  )

Question 4

border_cities_mex = us_cities %>%
  filter(dist_to_mexico < 160)

border_citiies_can = us_cities %>%
  filter(dist_to_canada < 160)

last_border_cities = us_cities %>%
  filter(dist_to_border < 160) %>%
  mutate(n = 1) %>%
  select(population, n) %>%
  summarise(pop = sum(population, na.rm = TRUE), total_cities = sum(n, na.rm = TRUE)) %>%
  st_drop_geometry()

kable(last_border_cities, caption = "Border Cities Based on 160 km Buffer",
      col.names = c("Total Population in Border Zone", "Number of Cities in Border Zone"),
      format.args = list(big.mark = ","))

Border Cities Based on 160 km Buffer
Total Population in Border Zone	Number of Cities in Border Zone
259,935,815	12,283

Total Us population = 328.2 million –> so 259.9/328.2 = 79% The article referenced in the lab directions estimates the total population in the border zone to be ~200 million, and my calculation gave just about 260 million so I would say the estimate matches my number but maybe our calculation gave a more precise estimation

map_last_border_cities = us_cities %>%
  filter(dist_to_border < 160)

pop_map_last_border_cities = map_last_border_cities %>%
  slice_max(population, n = 10)



ggplot() +
  geom_sf(data = map_last_border_cities, aes(col = dist_to_border), size = .1) +
  geom_sf(data = pop_map_last_border_cities, col = "black") +
  geom_sf(data = conus_string) +
  scale_color_gradient(low = "orange", high = "darkred") +
  ggthemes::theme_map() +
  labs(title = paste("Cities Located within Border Zone w/ Ten most Populated Cities")) +
  ggrepel::geom_label_repel(
    data = pop_map_last_border_cities,
    aes(label = city, geometry = geometry),
    stat = "sf_coordinates",
    size = 4
  )

Geography 176A

Lab 03: Distances and Projections

Wesley Noble

08-20-2020

Libraries

Question 1

Question 2

Question 3

Question 4