library(tidyverse)
library(sf)
library(gmRi)
# Following along here
# https://www.findingyourway.io/blog/2018/02/28/2018-02-28_great-circles-with-sf-and-leaflet/
raw_journey_data <- tribble(
~start.long, ~start.lat, ~end.long, ~end.lat, ~name,
-76.478645, 39.604256, -77.878035, 34.226766, "Jarrettsville to Wilmington",
-77.878035, 34.226766, -83.527100, 10.593577, "Wilmington to Costa Rica",
-83.527100, 10.593577, -90.801365, 29.795008, "Costa Rica to Thibodaux",
-90.801365, 29.795008, -88.797574, 30.393609, "Thibodaux to Ocean Springs",
-88.797574, 30.393609, -88.561524, 30.365844, "Ocean Springs to Pascagoula",
-88.561524, 30.365844, -70.255992, 43.651484, "Pascagoula to Portland",
)
# Change to sf
start_locs <- raw_journey_data %>%
select(
start.long,
start.lat
) %>%
setNames(c("long", "lat")) %>%
mutate(journey_id = row_number())
end_locs <- raw_journey_data %>%
select(
end.long,
end.lat
) %>%
setNames(c("long", "lat")) %>%
mutate(journey_id = row_number())
# Make linestrings from the start/end coordinates
journey_data_linestrings <- start_locs %>%
bind_rows(end_locs) %>%
st_as_sf(coords = c("long", "lat")) %>%
group_by(journey_id) %>%
arrange(journey_id) %>%
summarise() %>%
st_cast("LINESTRING")
journey_data_linestrings <- st_set_crs(journey_data_linestrings, st_crs(4326))
journey_data <- raw_journey_data
st_geometry(journey_data) <- st_geometry(journey_data_linestrings)
# Convert linestrings to matrices, then lists
list_of_linestrings <- raw_journey_data %>%
select(-name) %>%
transpose() %>%
map(~ matrix(flatten_dbl(.), nrow = 2, byrow = TRUE)) %>%
map(st_linestring)
# collect the features
collection_sf <- list_of_linestrings %>%
st_sfc(crs = 4326) %>%
st_sf(geometry = .)
# Bind to the raw
collection_sf <- collection_sf %>%
bind_cols(raw_journey_data) %>%
st_segmentize(units::set_units(50, km))
library(rnaturalearth)
world_sf <- ne_countries("medium", returnclass = "sf")
# Map
ggplot() +
geom_sf(data = world_sf) +
geom_sf(data = collection_sf, aes(color = name),
linewidth = 1) +
coord_sf(xlim = c(-95, -65), ylim = c(10, 45))
