rayshader (version 0.25.2)

render_polygons: Render Polygons

Description

Adds 3D polygons to the current scene, using latitude/longitude or coordinates in the reference system defined by the extent object.

Usage

render_polygons(
  polygon,
  extent,
  color = "red",
  top = 1,
  bottom = NA,
  data_column_top = NULL,
  data_column_bottom = NULL,
  heightmap = NULL,
  scale_data = 1,
  parallel = FALSE,
  holes = 0,
  lit = TRUE,
  light_altitude = c(45, 30),
  light_direction = c(315, 135),
  light_intensity = 0.3,
  clear_previous = FALSE
)

Arguments

polygon

`sf` object, "SpatialPolygon" `sp` object, or xy coordinates of polygon represented in a way that can be processed by `xy.coords()`. If xy-coordinate based polygons are open, they will be closed by adding an edge from the last point to the first.

extent

A `raster::Extent` object with the bounding box for the height map used to generate the original map.

color

Default `black`. Color of the polygon.

top

Default `1`. Extruded top distance. If this equals `bottom`, the polygon will not be extruded and just the one side will be rendered.

bottom

Default `0`. Extruded bottom distance. If this equals `top`, the polygon will not be extruded and just the one side will be rendered.

data_column_top

Default `NULL`. A string indicating the column in the `sf` object to use to specify the top of the extruded polygon.

data_column_bottom

Default `NULL`. A string indicating the column in the `sf` object to use to specify the bottom of the extruded polygon.

heightmap

Default `NULL`. Automatically extracted from the rgl window--only use if auto-extraction of matrix extent isn't working. A two-dimensional matrix, where each entry in the matrix is the elevation at that point. All points are assumed to be evenly spaced.

scale_data

Default `1`. If specifying `data_column_top` or `data_column_bottom`, how much to scale that value when rendering.

parallel

Default `FALSE`. If `TRUE`, polygons will be extruded in parallel, which may be faster (depending on how many geometries are in `polygon`).

holes

Default `0`. If passing in a polygon directly, this specifies which index represents the holes in the polygon. See the `earcut` function in the `decido` package for more information.

lit

Default `TRUE`. Whether to light the polygons.

light_altitude

Default `c(45, 60)`. Degree(s) from the horizon from which to light the polygons.

light_direction

Default `c(45, 60)`. Degree(s) from north from which to light the polygons.

light_intensity

Default `0.3`. Intensity of the specular highlight on the polygons.

clear_previous

Default `FALSE`. If `TRUE`, it will clear all existing polygons.

Examples

# NOT RUN {
#Render the county borders as polygons in Monterey Bay
montereybay %>%
  sphere_shade(texture = "desert") %>%
  add_shadow(ray_shade(montereybay,zscale=50)) %>%
  plot_3d(montereybay,water=TRUE, windowsize=800, watercolor="dodgerblue")
render_camera(theta=140,  phi=55, zoom = 0.85, fov=30)

#We will apply a negative buffer to create space between adjacent polygons:
mont_county_buff = sf::st_simplify(sf::st_buffer(monterey_counties_sf,-0.003), dTolerance=0.001)

render_polygons(mont_county_buff, 
                extent = attr(montereybay,"extent"), top=10,
                parallel=TRUE)
render_snapshot()

#We can specify the bottom of the polygons as well. Here I float the polygons above the surface
#by specifying the bottom argument. We clear the previous polygons with `clear_previous = TRUE`.
render_camera(theta=-60,  phi=20, zoom = 0.85, fov=0)
render_polygons(mont_county_buff, 
                extent = attr(montereybay,"extent"), bottom = 190, top=200,
                parallel=TRUE,clear_previous=TRUE)
render_snapshot()

#We can set the height of the data to a column in the sf object: we'll use the land area.
#We'll have to scale this value because it's max value is 2.6 billion:
render_camera(theta=-60,  phi=60, zoom = 0.85, fov=30)
render_polygons(mont_county_buff, 
                extent = attr(montereybay,"extent"), data_column_top = "ALAND",
                scale_data = 300/(2.6E9), color="chartreuse4",
                parallel=TRUE,clear_previous=TRUE)
render_snapshot()        

#This function also works with `render_highquality()`
render_highquality(samples=400, clamp_value=10)
rgl::rgl.close()
# }