day 2

2019-11-02-lines.R

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+library(rvest)
+library(sf)
+library(grid)
+library(gridExtra)
+library(rnaturalearth)
+library(rnaturalearthdata)
+library(hrbrthemes)
+library(tidyverse)
+
+# get the world without antarctica
+ne_countries(scale = "medium", returnclass = "sf") %>%
+  filter(name != "Antarctica") -> world
+
+# figure out the center of Maine
+me <- which(state.abb == "ME")
+
+st_sfc(st_point(c(state.center$x[me], state.center$y[me]))) %>%
+  st_set_crs("+proj=longlat +datum=WGS84 +no_defs") %>%
+  st_transform(crs = "+proj=eqearth +wktext") -> maine_center # need this in the eqearth CRS (see note below)
+
+# read the web page
+pg <- read_html("https://www.census.gov/foreign-trade/statistics/state/data/me.html")
+
+html_nodes(pg, "table") %>%  # parse the page
+  .[[2]] %>%
+  html_table() %>%
+  as_tibble() %>%
+  janitor::clean_names() %>%
+  select(country, x2018_value) %>%
+  mutate(x2018_value = parse_number(x2018_value)) %>%
+  filter(!grepl("Total", country)) %>%
+  mutate(country = case_when( # clean up the countries
+    country == "Macau" ~ "Macao",
+    country == "Korea, South" ~ "Korea",
+    TRUE ~ country
+  )) %>%
+  arrange(desc(x2018_value)) %>%
+  slice(1:20) %>%
+  left_join(world, by = c("country" = "name")) %>% # get the geometries for the target countries so we can get their centers
+  mutate(to = suppressWarnings(st_centroid(geometry)) %>% st_transform(crs = "+proj=eqearth +wktext")) %>% # need to transform (see note below)
+  select(country, x2018_value, to) %>%
+  mutate(maine = maine_center) -> xdf # temporary variable
+
+# we're using geom_curve() so we need regular values
+# these values need to be pre-transformed since we're going to use geom_curve() instead of geom_sf()
+st_coordinates(xdf$maine) %>%
+  as_tibble() %>%
+  set_names(c("from_x", "from_y")) %>%
+  bind_cols(
+    st_coordinates(xdf$to) %>%
+      as_tibble() %>%
+      set_names(c("to_x", "to_y")),
+    select(xdf, country, x2018_value)
+  ) -> maine_exports_to
+
+# for displaying a data table next to the map
+as_tibble(maine_exports_to) %>%
+  select(Country = country, Exports = x2018_value) %>%
+  mutate(Exports = glue::glue("{scales::comma(Exports)}M USD")) %>%
+  tableGrob(
+    rows = NULL,
+    theme = ttheme_default(
+      core = list(
+        fg_params = list(
+          fontfamily = font_rc,
+          hjust = c(rep(0, 20), rep(1, 20)),
+          x = c(rep(0.1, 20), rep(0.9, 20))
+        )
+      )
+    )
+  ) -> tabl
+
+# map time#
+ggplot() +
+  geom_sf(data = world, size = 0.125, fill = "#3B454A", color = "#b2b2b2") +
+  geom_curve(
+    data = maine_exports_to, aes(x = from_x, y = from_y, xend = to_x, yend = to_y, color = x2018_value, size = x2018_value),
+    curvature = 0.2, arrow = arrow(length = unit(10, "pt"), type = "closed"),
+  ) +
+  guides(
+    color = guide_legend(reverse = TRUE)
+  ) +
+  annotation_custom(tabl, xmin = -16920565, xmax = -14000000,  ymin=761378/2.25, ymax = 761378) + # values are in eqarea meters
+  coord_sf(crs = "+proj=eqearth +wktext") +
+  scale_color_distiller(
+    palette = "RdYlBu", trans = "log10", name = "(Size & color\nlog10 scale)", label = scales::comma,
+    breaks = c(30, 50, 100, 300, 1000), limits = c(15, 1500)
+  ) +
+  scale_size_continuous(
+    trans = "log10", range = c(0.75, 3),
+    breaks = c(30, 50, 100, 300, 1000), limits = c(15, 1500),
+    guide = FALSE
+  ) +
+  theme_ft_rc(grid="") +
+  labs(
+    x = NULL, y = NULL,
+    title = "Top 20 (by Value) Export Destinations for Maine Goods (2018)",
+    caption = "Data source: Census Bureau Foreign Trade <https://www.census.gov/foreign-trade/statistics/state/data/me.html>\nhttps://git.rud.is/hrbrmstr/y2019-30daymapchallenge • #30DayMapChallenge"
+  ) +
+  theme_ft_rc(grid="") +
+  theme(legend.key.height = unit(2.8, "lines")) +
+  theme(legend.position = c(0.2, 0.3)) +
+  theme(axis.text.x = element_blank())