happign (version 0.3.8)

get_wfs: Download data from IGN WFS layer

Description

Download features from the IGN Web Feature Service (WFS) using a spatial predicate, an ECQL attribute query, or both.

Usage

get_wfs(
  x = NULL,
  layer = NULL,
  predicate = bbox(),
  query = NULL,
  verbose = TRUE
)

Value

An object of class sf.

Arguments

x

sf, sfc or NULL. If NULL, no spatial filter is applied and query must be provided.

layer

character; name of the WFS layer. Must correspond to a layer available on the IGN WFS service (see get_layers_metadata()).

predicate

list; a spatial predicate definition created with helper such as bbox(), intersects(), within(), contains(), touches(), crosses(), overlaps(), equals(), dwithin(), beyond() or relate(). See spatial_predicates for more info.

query

character; an ECQL attribute query. When both x and query are provided, the spatial predicate and the attribute query are combined.

verbose

logical; if TRUE, display progress information and other informative message.

Details

• get_wfs use ECQL language : a query language created by the OpenGeospatial Consortium. More info about ECQL language can be found here.

See Also

get_layers_metadata()

Examples

if (FALSE) {
library(sf)

# Load a geometry
x <- read_sf(system.file("extdata/penmarch.shp", package = "happign"))

# Retrieve commune boundaries intersecting x
commune <- get_wfs(
  x = x,
  layer = "LIMITES_ADMINISTRATIVES_EXPRESS.LATEST:commune"
)

plot(st_geometry(commune), border = "firebrick")

# Attribute-only query (no spatial filter)

# If unknown, available attributes can be retrieved using `get_wfs_attributes()`
attrs <- get_wfs_attributes("LIMITES_ADMINISTRATIVES_EXPRESS.LATEST:commune")
print(attrs)

plou_communes <- get_wfs(
  x = NULL,
  layer = "LIMITES_ADMINISTRATIVES_EXPRESS.LATEST:commune",
  query = "nom_officiel ILIKE 'PLOU%'"
)
plot(st_geometry(plou_communes))

# Multiple Attribute-only query (no spatial filter)
plou_inf_2000 <- get_wfs(
  x = NULL,
  layer = "LIMITES_ADMINISTRATIVES_EXPRESS.LATEST:commune",
  query = "nom_officiel ILIKE 'PLOU%' AND population < 2000"
)
plot(st_geometry(plou_communes))
plot(st_geometry(plou_inf_2000), col = "firebrick", add = TRUE)

# Spatial predicate usage

layer <- "BDCARTO_V5:rond_point"

bbox_feat <- get_wfs(commune, layer, predicate = bbox())
plot(st_geometry(bbox_feat), col = "red")
plot(st_geometry(commune), add = TRUE)

intersects_feat <- get_wfs(commune, layer, predicate = intersects())
plot(st_geometry(intersects_feat), col = "red")
plot(st_geometry(commune), add = TRUE)

dwithin_feat <- get_wfs(commune, layer, predicate = dwithin(5, "kilometers"))
plot(st_geometry(dwithin_feat), col = "red")
plot(st_geometry(commune), add = TRUE)
}