knitr::opts_chunk$set( collapse = TRUE, comment = " " ) library(leaflet) library(sf) library(nlgeocoder)
nl_geocode
provides a quick and easy way to geocode labels of locations in
The Netherlands. It will return points or centroids with metadata, but no polylines or polygons.
nl_geocode
uses the pdok webservice for geo location and is designed to be similar to ggmap:
for each (address) label the most probable location (i.e. according to the pdok service) will be
returned.
By default, nl_geocode
will search for addresses.
library(nlgeocoder) res <- nl_geocode("Martinikerkhof 3 Groningen") print(res["weergavenaam"])
For addresses a lot of information is available:
colnames(res)
You can also search for multiple addresses at once.
locations <- c("Martinikerkhof 3", "st jansstr 4 groningen", "9726AE 4", "9711 ME 1") res <- nl_geocode(locations) data.frame(query = locations, result = res$weergavenaam)
As you can see, the address doesn't need to be an exact match. Uppercases are ignored.
Besides addresses, you can also search for places, municipalities, provinces, roads and many more. See the LocatieServer API documentation complete list of types you can choose from.
You can restrict the output of nl_geocode
to municipalities only:
res <- nl_geocode("Groningen", type = "gemeente") res[c("weergavenaam","type")]
You can also restrict the output to places:
res <- nl_geocode("Groningen", type = "woonplaats") res$weergavenaam res$type
If you are only interested in results in a particular area (for instance a province or municipality) you can use the fq
parameter.
res <- nl_geocode("Hoofdstraat", fq = "provincienaam:Groningen") res$weergavenaam res$provincienaam
By default, nl_geocode
will return a sf
object with coordinates in the
coordinate reference system WGS84 (EPSG:4326).
res <- nl_geocode("Martinikerkhof 3 Groningen") st_crs(res)["epsg"]
It also possible to specify that the coordinates should be in RD_New (EPSG:28992), the Dutch coordinate reference system.
res <- nl_geocode("Martinikerkhof 3 Groningen", output = "rd") st_crs(res)["epsg"]
You can also use the nl_geocode_rd
function instead:
res <- nl_geocode_rd("Martinikerkhof 3 Groningen") st_crs(res)["epsg"]
You can use the parameter output
to indicate that you only want the labels, and not the geometry.
res <- nl_geocode("Martinikerkhof 3 Groningen", output = "data.frame") class(res)
Plotting the output on a map, because by default nl_geocode
returns an sf
object.
data("addresses")
knitr::kable(addresses)
library(leaflet) poi_geocoded <- nl_geocode(addresses$Address) leaflet(width = "100%", height=600) %>% addPdokTiles("gray") %>% addCircleMarkers(data = poi_geocoded, popup = ~weergavenaam)
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