Get a layer from a web feature service

This function constructs a URL request from its arguments and either reads in the resulting vector layer as a sf object or returns the number of features that are requested. The request is made up of key-value pairs and additional key-value pairs can be passed to the function. The full documentation for the WFS standard can be consulted from https://www.ogc.org/standard/wfs/.

get_feature_wfs(
  wfs,
  version = "2.0.0",
  layername = NULL,
  crs = NULL,
  bbox = NULL,
  filter = NULL,
  cql_filter = NULL,
  output_format = NULL,
  property_name = NULL,
  result_type = c("results", "hits"),
  ...
)

Arguments

wfs

Web address for the service which you want to query features from

version

Version number for the service. For instance "2.0.0".

layername

Optional name of a layer hosted by the web feature service

crs

Optional coordinate reference system to represent the features. For instance "EPSG:31370".

bbox

Optional bounding box. Pass this as a named vector with names "xmin", "xmax", "ymin", "ymax".

filter

Optional standard OGC filter specification

cql_filter

Optional Contextual Query Language filter. This currently only works if the WFS is hosted on a GeoServer.

output_format

Optional output format supported by the WFS.

property_name

Optional character string. Which fields or columns to return? If you want to specify multiple columns, separate them by a comma. The column containing the feature geometry is usually called geom, geometry or SHAPE.

result_type

For version "2.x.x", this can be either "results" (default) or "hits". The former returns the requested features, the latter returns the number of requested features.

...

Additional key-value pairs passed on to the WFS query.

Details

See https://inbo.github.io/tutorials/tutorials/spatial_wfs_services/ for more information.

See also

Other topics on using web services: add_wms_be_cartoweb(), add_wmts_nl_brt(), get_coverage_wcs()

Examples

if (FALSE) {
vlaanderen <- get_feature_wfs(
  wfs = paste0(
    "https://eservices.minfin.fgov.be/",
    "arcgis/services/R2C/Regions/MapServer/WFSServer"
  ),
  layername = "regions",
  crs = "EPSG:31370",
  filter = paste0(
    "<Filter><PropertyIsEqualTo><PropertyName>",
    "regions:NameDUT</PropertyName><Literal>'Vlaams Gewest'",
    "</Literal></PropertyIsEqualTo></Filter>"
  )
)
}