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Use ggsvg to add a layer with icons at feature locations

Source: R/layer_icon.R
layer_icon.Rd

Use the ggsvg::geom_point_svg() function to plot icons using the centroids from the input simple feature object to set the icon location.

Usage

layer_icon(
  data = NULL,
  iconname_col = "icon",
  icon = NULL,
  px = NULL,
  source = NULL,
  svg = NULL,
  crs = getOption("maplayer.crs", default = 3857),
  ...
)

geom_sf_icon(
  data = NULL,
  iconname_col = "icon",
  icon = NULL,
  px = NULL,
  source = NULL,
  svg = NULL,
  crs = getOption("maplayer.crs", default = 3857),
  ...
)

Arguments

data

A sf object. Any objects with polygon geometry are converted to points using sf::st_centroid().

iconname_col

The column name in the input data to use as the icon name. If the name matches multiple icons, the first match from map_icons is used. You may provide a px or source value to select a different match if needed but, in that case, all icons must use the same px or source value. Note that the icon column should not be mapped with ggplot2::aes().

icon

Icon name. Default NULL. If icon is provided, iconname_col is ignored. See map_icons$name for supported options.

px

Icon size in pixels. See map_icons$px for supported options. Optional but may be necessary to differentiate icons with duplicate names.

source

Icon source. See map_icons$repo for supported options. Optional but may be required to differentiate icons with duplicate names.

svg

Optional. Custom file path or URL with SVG to pass to svg parameter for ggsvg::geom_point_svg(). If icon is provided, svg is ignored.

crs

Coordinate reference system; defaults to NULL.

...

Arguments passed on to ggsvg::geom_point_svg

defaults

Advanced option. A named list of default values for new aesthetics. In general this is not necessary when using css() aesthetics, as a default value will be determined based upon the CSS property e.g. stroke property will have a default value of "black"

Set `options(GGSVG_DEBUG = TRUE)` for some verbose debugging which will cause `ggsvg` to output (to the console) the final SVG for each and every element in the plot.

See also

ggsvg::geom_point_svg() map_icons

Examples

nc <- getdata::get_location(type = system.file("shape/nc.shp", package = "sf"), crs = 3857)

basemap <-
  ggplot2::ggplot() +
  ggplot2::theme_void() +
  layer_location_data(data = nc)

# icon can be set by name matching a name from map_icons
basemap +
  layer_icon(data = nc, icon = "point-start", size = 8)


# layer_icon can also use a column from the sf object
nc$icon <- rep(c("1", "2", "3", "4"), nrow(nc) / 4)

basemap +
  layer_icon(data = nc, iconname_col = "icon", size = 6)