tmaptools: geocode_OSM – R documentation

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geocode_OSM

Geocodes a location using OpenStreetMap Nominatim

Description

Geocodes a location (based on a search query) to coordinates and a bounding box. Similar to geocode from the ggmap package. It uses OpenStreetMap Nominatim. For processing large amount of queries, please read the usage policy (https://operations.osmfoundation.org/policies/nominatim/).

Usage

geocode_OSM(
  q,
  projection = NULL,
  return.first.only = TRUE,
  keep.unfound = FALSE,
  details = FALSE,
  as.data.frame = NA,
  as.sf = FALSE,
  geometry = c("point", "bbox"),
  server = "https://nominatim.openstreetmap.org"
)

Arguments

`q`	a character (vector) that specifies a search query. For instance `"India"` or `"CBS Weg 11, Heerlen, Netherlands"`.
`projection`	projection in which the coordinates and bounding box are returned. See `st_crs` for details. By default latitude longitude coordinates (EPSG 4326).
`return.first.only`	Only return the first result
`keep.unfound`	Keep list items / data.frame rows with `NA`s for unfound search terms. By default `FALSE`
`details`	provide output details, other than the point coordinates and bounding box
`as.data.frame`	Return the output as a `data.frame`. If `FALSE`, a list is returned with at least two items: `"coords"`, a vector containing the coordinates, and `"bbox"`, the corresponding bounding box. By default false, unless `q` contains multiple queries. If `as.sf = TRUE` (see below), `as.data.frame` will set to `TRUE`.
`as.sf`	Return the output as `sf` object. If `TRUE`, `return.first.only` will be set to `TRUE`. Two geometry columns are added: `bbox` and `point`. The argument `geometry` determines which of them is set to the default geometry.
`geometry`	When `as.sf`, this argument determines which column (`bbox` or `point`) is set as geometry column. Note that the geometry can be changed afterwards with `st_set_geometry`.
`server`	OpenStreetMap Nominatim server name. Could also be a local OSM Nominatim server.

Value

If as.sf then a sf object is returned. Else, if as.data.frame, then a data.frame is returned, else a list.

Examples

## Not run: 
if (require(tmap)) {
    geocode_OSM("India")
    geocode_OSM("CBS Weg 1, Heerlen")
    geocode_OSM("CBS Weg 1, Heerlen", projection = 28992)

    data(metro)

    # sample 5 cities from the metro dataset
    five_cities <- metro[sample(length(metro), 5), ]

    # obtain geocode locations from their long names
    five_cities_geocode <- geocode_OSM(five_cities$name_long, as.sf = TRUE)

    # change to interactive mode
    current.mode <- tmap_mode("view")

    # plot metro coordinates in red and geocode coordinates in blue
    # zoom in to see the differences
    tm_shape(five_cities) +
    	tm_dots(col = "blue") +
    tm_shape(five_cities_geocode) +
    	tm_dots(col = "red")

    # restore current mode
    tmap_mode(current.mode)
}

## End(Not run)

tmaptools

Thematic Map Tools

v3.1-1

GPL-3

Authors

Martijn Tennekes [aut, cre]

Initial release

2021-01-19