generate_polygon_overlay: Generate Polygon Overlay

In tylermorganwall/rayshader: Create Maps and Visualize Data in 2D and 3D

Generate Polygon Overlay

Description

Transforms an input 'sf' object into an image overlay for the current height map.

Usage

generate_polygon_overlay(
  geometry,
  extent,
  heightmap = NULL,
  width = NA,
  height = NA,
  resolution_multiply = 1,
  offset = c(0, 0),
  data_column_fill = NULL,
  linecolor = "black",
  palette = "white",
  linewidth = 1
)

Arguments

geometry	An 'sf' object with POLYGON geometry.
extent	Either an object representing the spatial extent of the scene (either from the 'raster', 'terra', 'sf', or 'sp' packages), a length-4 numeric vector specifying 'c("xmin", "xmax","ymin","ymax")', or the spatial object (from the previously aforementioned packages) which will be automatically converted to an extent object.
heightmap	Default 'NULL'. The original height map. Pass this in to extract the dimensions of the resulting overlay automatically.
width	Default 'NA'. Width of the resulting overlay. Default the same dimensions as height map.
height	Default 'NA'. Width of the resulting overlay. Default the same dimensions as height map.
resolution_multiply	Default '1'. If passing in 'heightmap' instead of width/height, amount to increase the resolution of the overlay, which should make lines/polygons/text finer. Should be combined with 'add_overlay(rescale_original = TRUE)' to ensure those added details are captured in the final map.
offset	Default 'c(0,0)'. Horizontal and vertical offset to apply to the polygon, in units of 'geometry'.
data_column_fill	Default 'NULL'. The column to map the polygon fill color to.
linecolor	Default 'black'. Color of the lines.
palette	Default 'black'. Single color, named vector color palette, or palette function. If this is a named vector and 'data_column_fill' is not 'NULL', it will map the colors in the vector to the names. If 'data_column_fill' is a numeric column, this will give a continuous mapping.
linewidth	Default '1'. Line width.

Value

Image overlay representing the input polygon data.

Examples

#Plot the counties around Monterey Bay, CA
if(run_documentation()) {
generate_polygon_overlay(monterey_counties_sf, palette = rainbow, 
                        extent = attr(montereybay,"extent"), heightmap = montereybay) %>%
 plot_map() 
}
if(run_documentation()) {
#These counties include the water, so we'll plot bathymetry data over the polygon
#data to only include parts of the polygon that fall on land.
water_palette = colorRampPalette(c("darkblue", "dodgerblue", "lightblue"))(200)
bathy_hs = height_shade(montereybay, texture = water_palette)

generate_polygon_overlay(monterey_counties_sf, palette = rainbow, 
                        extent = attr(montereybay,"extent"), heightmap = montereybay) %>%
 add_overlay(generate_altitude_overlay(bathy_hs, montereybay, start_transition = 0)) %>%
 plot_map()
}
if(run_documentation()) {
#Add a semi-transparent hillshade and change the palette, and remove the polygon lines
montereybay %>%
 sphere_shade(texture = "bw") %>%
 add_overlay(generate_polygon_overlay(monterey_counties_sf, 
                        palette = terrain.colors, linewidth=NA,
                        extent = attr(montereybay,"extent"), heightmap = montereybay),
                        alphalayer=0.7) %>%
 add_overlay(generate_altitude_overlay(bathy_hs, montereybay, start_transition = 0)) %>%
 add_shadow(ray_shade(montereybay,zscale=50),0) %>%
 plot_map()
}
if(run_documentation()) {
#Map one of the variables in the sf object and use an explicitly defined color palette
county_palette = c("087" = "red",    "053" = "blue",   "081" = "green", 
                  "069" = "yellow", "085" = "orange", "099" = "purple") 
montereybay %>%
 sphere_shade(texture = "bw") %>%
 add_shadow(ray_shade(montereybay,zscale=50),0) %>%
 add_overlay(generate_polygon_overlay(monterey_counties_sf, linecolor="white", linewidth=3,
                        palette = county_palette, data_column_fill = "COUNTYFP",
                        extent = attr(montereybay,"extent"), heightmap = montereybay),
                        alphalayer=0.7) %>%
 add_overlay(generate_altitude_overlay(bathy_hs, montereybay, start_transition = 0)) %>%
 add_shadow(ray_shade(montereybay,zscale=50),0.5) %>%
 plot_map()
}

tylermorganwall/rayshader documentation built on May 3, 2024, 6:03 p.m.