Official keys — bkg

Retrieve geographical names associated with official municipality keys and regional keys. To retrieve their polygon geometries, see bkg_admin.

These functions interface the wfs_gnde product of the BKG.

Usage

bkg_ags(..., filter = NULL, properties = NULL, max = NULL)

bkg_ars(..., filter = NULL, properties = NULL, max = NULL)

Arguments

...

Used to construct CQL filters. Dot arguments accept an R-like syntax that is converted to CQL queries internally. These queries basically consist of a property name on the left, an aribtrary vector on the right, and an operator that links both sides. If multiple queries are provided, they will be chained with AND. The following operators and their respective equivalents in CQL and XML are supported:

R	CQL	XML
`==`	`=`	`PropertyIsEqualTo`
`!=`	`<>`	`PropertyIsNotEqualTo`
`<`	`<`	`PropertyIsLessThan`
`>`	`>`	`PropertyIsGreaterThan`
`>=`	`>=`	`PropertyIsGreaterThanOrEqualTo`
`<=`	`<=`	`PropertyIsLessThanOrEqualTo`
`%LIKE%`	`LIKE`	`PropertyIsLike`
`%ILIKE%`	`ILIKE`
	`%in%`	`IN`

To construct more complex queries, you can use the filter argument to pass CQL queries directly. Also note that you can switch between CQL and XML queries using options(ffm_query_language = "xml"). See also wfs_filter.

filter

A character string containing a valid CQL or XML filter. This string is appended to the query constructed through .... Use this argument to construct more complex filters. Defaults to NULL.

properties

Vector of columns to include in the output.

max

Maximum number of results to return.

Value

A dataframe containing the respective identifier and geographical names related to their state, government region, district and municipality. bkg_ars additionally returns the name of the administrative association.

Query language

While other WFS interfaces like bkg_admin allow querying using CQL or XML, bkg_ags and bkg_ars (using the GNDE service) ONLY support XML. This has implications for the allowed query filters (see wfs_filter).

Examples

if (FALSE) { # getFromNamespace("ffm_run_examples", ns = "ffm")()
# Either get geographical names for identifiers
bkg_ars(ars == "01")

# ... or identifiers for geographical names
bkg_ars(gemeinde == "Köln")
}