Exploring triangles and points in 3D with mapdeck

mapdeck_triangles.R

nc <- sf::read_sf(system.file("shape/nc.shp", package="sf"))
bb <- sf::st_bbox(nc)
bb <- bb + c(-2, -2, 2, 2)
topo <- marmap::as.raster(marmap::getNOAA.bathy(bb["xmax"], bb["xmin"], bb["ymax"], bb["ymin"], 
																								resolution = 2))

triangles <- sf::st_cast(sfdct::ct_triangulate(nc, a = .005))

elevate_triangles <- function(g, r) {
	## assuming geometry of POLYGON
	sf::st_polygon(list(cbind(g[[1]], raster::extract(r, g[[1]]))))
}

elevate_sf <- function(x, r, exag = 1) {
	sf::st_set_geometry(x, sf::st_sfc(purrr::map(sf::st_geometry(x), elevate_triangles, r = r * exag), crs = sf::st_crs(x)))
}
library(mapdeck)

x <- elevate_sf(triangles, topo)
p <- st_cast(x, "MULTIPOINT")
sc <- as.data.frame(sf::st_coordinates(p)) %>% dplyr::mutate(Z = Z * 10)
key <- Sys.getenv("MAPBOX_TOKEN")

mapdeck(
	token = key, style = 'mapbox://styles/mapbox/dark-v9', location = c(145, -37.8), zoom = 10) %>%
	add_path(
		data = roads, stroke_colour = "RIGHT_LOC", layer_id = "path_layer"
	)

mapdeck(token = key, style = 'mapbox://styles/mapbox/dark-v9', location = c(mean(bb[c("xmin", "xmax")]), mean(bb[c("ymin", "ymax")])), zoom = 5) %>% 
	add_polygon(data = x, layer_id = "polylayer", fill_colour = "NAME") %>% 
	add_path(data = sf::st_cast(x, "MULTILINESTRING"), layer_id = "pathlayer") %>%
	add_pointcloud(data = sc, lon = "X", lat = "Y", elevation = "Z", 
								 layer_id = "abc", stroke_width = 1, fill_colour = "L1")