Render a WMS layer as a raster

Issues a GetMap request and returns the rendered image georeferenced as a terra::SpatRaster. Unlike a WFS read this gives you the server's own cartography — useful for basemaps, orthophotos and any layer published only as a picture.

Usage

argentum_read_wms(
  x,
  layer,
  bbox,
  crs = NULL,
  width = NULL,
  height = NULL,
  style = NULL,
  format = NULL,
  transparent = TRUE,
  quiet = arg_opt("argentum.quiet")
)

Arguments

x

An organization name from argentum_organizations(), or a WMS URL.

layer

Layer name, or a character vector of names to be drawn in order, first at the bottom.

bbox

Extent to render, as c(xmin, ymin, xmax, ymax) or any object accepted by sf::st_bbox(). Required: WMS has no "everything" request.

crs

CRS of bbox and of the output, e.g. "EPSG:4326" or 4326. Defaults to "EPSG:4326", or to the CRS of bbox if it carries one.

width, height

Image size in pixels. If only one is given, the other is derived from the aspect ratio of bbox. If neither is given, width defaults to 800.

style

Optional named style, or one per layer.

format

MIME type to request. NULL (default) negotiates one from the formats the service advertises for GetMap, preferring PNG, which keeps transparency. Pass a value such as "image/jpeg" to force it.

transparent

Request a transparent background.

quiet

Suppress progress messages.

Value

A terra::SpatRaster with the CRS set, ready to combine with vector data read via argentum_read_wfs().

See also

argentum_wms_legend() for the matching legend graphic.

Examples

# \donttest{
r <- argentum_read_wms(
  "https://wms.ign.gob.ar/geoserver/ows",
  layer = "ign:provincia",
  bbox  = c(-59, -35, -57, -34),
  width = 800
)
#> Requesting WMS 1.3.0 capabilities from <https://wms.ign.gob.ar/geoserver/ows>
#> ℹ Rendering ign:provincia at 800x400
#> Warning: [rast] unknown extent
#> ✔ Rendered 4 bands.
#> ℹ Rendering ign:provincia at 800x400

#> ✔ Rendering ign:provincia at 800x400 [565ms]
#> 
terra::plotRGB(r)

# }