Shadow layer — viz_shadow • geovizr

The viz_shadow function adds a shadow effect to map elements, typically used to enhance depth perception for shapes, symbols, or extruded visualizations. The layer is rendered in SVG and can be applied globally or to specific geometries.

Usage

viz_shadow(
  map,
  id = NULL,
  dx = 0,
  dy = 0,
  blur = 0,
  opacity = 1,
  fill = NULL,
  stroke = NULL,
  strokeWidth = NULL,
  coords = "geo",
  ...
)

Arguments

map: A geovizr map object created using viz_create.
id: character. Optional. Unique layer id.
dx: numeric. Optional. Horizontal shadow offset (default 0).
dy: numeric. Optional. Vertical shadow offset (default 0).
blur: numeric. Optional. Blur intensity of the shadow (default 0).
opacity: numeric. Optional. Shadow opacity (default 1).
fill: character or function. Optional. Shadow fill color.
stroke: character or function. Optional. Shadow stroke color.
strokeWidth: numeric. Optional. Shadow stroke width.
coords: character. Optional. Coordinate system (default "geo"). Use "svg" if coordinates are already expressed in SVG space.
...: Additional parameters

Value

A modified `geoviz` map object with a new effect added. Rendering is performed using viz_render().

Examples

library(sf)
world <- st_read(
  system.file("gpkg/world.gpkg", package = "geovizr"),
  quiet = TRUE
)
aus <- world[world$ISO3 == "AUS", ]

viz_create(margin = 5) |>
  viz_shadow(id = "my_shadow_effect", stdDeviation = 2.5, dx = 5, dy = 5) |>
  viz_path(datum = aus, fill = "#38896F", filter = "url(#my_shadow_effect)") |>
  viz_render()