R: Get a Google Map.

get_googlemap {ggmap}

R Documentation

Get a Google Map.

Description

get_googlemap() queries the Google Maps Static API version 2 to download a static map. Note that in most cases by using this function you are agreeing to the Google Maps API Terms of Service at https://cloud.google.com/maps-platform/terms/. Note that as of mid-2018, registering with Google Cloud to obtain an API key is required to use any of Google's services, including get_googlemap(). Usage and billing may apply, see the links under See Also further down in this documentation for more details.

Usage

get_googlemap(
  center = c(lon = -95.3632715, lat = 29.7632836),
  zoom = 10,
  size = c(640, 640),
  scale = 2,
  format = c("png8", "gif", "jpg", "jpg-baseline", "png32"),
  maptype = GOOGLE_VALID_MAP_TYPES,
  language = "en-EN",
  messaging = FALSE,
  urlonly = FALSE,
  filename = NULL,
  color = c("color", "bw"),
  force = FALSE,
  where = tempdir(),
  archiving = FALSE,
  ext = "com",
  inject = "",
  region,
  markers,
  path,
  visible,
  style,
  ...
)

Arguments

`center`	the center of the map; either a longitude/latitude numeric vector or a string containing a location, in which case `geocode()` is called with `source = "google"`. (default: `c(lon = -95.3632715, lat = 29.7632836)`, a reference to Houston, Texas)
`zoom`	map zoom; an integer from 3 (continent) to 21 (building), default value 10 (city)
`size`	rectangular dimensions of map in pixels - horizontal x vertical - with a max of c(640, 640). this parameter is affected in a multiplicative way by scale.
`scale`	multiplicative factor for the number of pixels returned possible values are 1, 2, or 4 (e.g. size = c(640,640) and scale = 2 returns an image with 1280x1280 pixels). 4 is reserved for google business users only. scale also affects the size of labels as well.
`format`	character string providing image format - png, jpeg, and gif formats available in various flavors
`maptype`	character string providing google map theme. options available are `"terrain"`, `"satellite"`, `"roadmap"`, and `"hybrid"`
`language`	character string providing language of map labels (for themes with them) in the format `"en-EN"`. not all languages are supported; for those which aren't the default language is used
`messaging`	turn messaging on/off
`urlonly`	return url only
`filename`	destination file for download (file extension added according to format). Default `NULL` means a random `tempfile()`.
`color`	color or black-and-white
`force`	if the map is on file, should a new map be looked up?
`where`	where should the file drawer be located (without terminating "/")
`archiving`	use archived maps. note: by changing to TRUE you agree to the one of the approved uses listed in the Google Maps API Terms of Service : https://cloud.google.com/maps-platform/terms/.
`ext`	domain extension (e.g. `"com"`, `"co.nz"`)
`inject`	character string to add to the url
`region`	borders to display as a region code specified as a two-character ccTLD ("top-level domain") value, see https://en.wikipedia.org/wiki/List_of_Internet_top-level_domains#Country_code_top-level_domains
`markers`	data.frame with first column longitude, second column latitude, for which google markers should be embedded in the map image, or character string to be passed directly to api
`path`	data.frame (or list of data.frames) with first column longitude, second column latitude, for which a single path should be embedded in the map image, or character string to be passed directly to api
`visible`	a location as a longitude/latitude numeric vector (or data frame with first column longitude, second latitude) or vector of character string addresses which should be visible in map extent
`style`	character string to be supplied directly to the api for the style argument or a named vector (see examples). this is a powerful complex specification, see https://developers.google.com/maps/documentation/maps-static/
`...`	...

Value

a ggmap object (a classed raster object with a bounding box attribute)

Author(s)

David Kahle david@kahle.io

Examples


## Not run:  requires Google API key, see ?register_google

## basic usage
########################################

(map <- get_googlemap(c(-97.14667, 31.5493)))
ggmap(map)

# plotting based on a colloquial name
# this requires a geocode() call, and needs that API
get_googlemap("waco, texas") %>% ggmap()

# different maptypes are available
get_googlemap("waco, texas", maptype = "satellite") %>% ggmap()
get_googlemap("waco, texas", maptype = "hybrid") %>% ggmap()

# you can get the url as follows
# see ?register_google if you want the key printed
get_googlemap(urlonly = TRUE)


## other usage
########################################

# markers and paths are easy to access
d <- function(x=-95.36, y=29.76, n,r,a){
  round(data.frame(
    lon = jitter(rep(x,n), amount = a),
    lat = jitter(rep(y,n), amount = a)
  ), digits = r)
}
(df <- d(n = 50, r = 3, a = .3))
map <- get_googlemap(markers = df, path = df, scale = 2)
ggmap(map)
ggmap(map, extent = "device") +
  geom_point(aes(x = lon, y = lat), data = df, size = 3, colour = "black") +
  geom_path(aes(x = lon, y = lat), data = df)

gc <- geocode("waco, texas", source = "google")
center <- as.numeric(gc)
ggmap(get_googlemap(center = center, color = "bw", scale = 2), extent = "device")

# the scale argument can be seen in the following
# (make your graphics device as large as possible)
ggmap(get_googlemap(center, scale = 1), extent = "panel") # pixelated
ggmap(get_googlemap(center, scale = 2), extent = "panel") # fine

# archiving; note that you must meet google's terms for this condition
map <- get_googlemap(archiving = TRUE)
map <- get_googlemap()
map <- get_googlemap()
ggmap(map)


# style
map <- get_googlemap(
  maptype = "roadmap",
  style = c(feature = "all", element = "labels", visibility = "off"),
  color = "bw"
)
ggmap(map)





## End(Not run)

[Package ggmap version 4.0.0 Index]