knitr::opts_chunk$set( collapse = TRUE, comment = "#>", fig.path = "README-" )
The mapsapi
package provides an interface to the Google Maps APIs, currently four of them:
Functions mp_directions
, mp_matrix
and mp_geocode
are used to access the Directions, Matrix and Geocode APIs, respectively. They return an xml_document
object (package xml2
) with the response contents.
Given a directions response, functions mp_get_routes
and mp_get_segments
can be used to process the response document into a spatial layer. Function mp_get_routes
gives each alternative as a separate line, while function mp_get_segments
gives each segment (that is, a portion of the route associated with specific driving instructions) as a separate line.
Given a distance matrix response, function mp_get_matrix
can be used to obtain distance/duration matrices.
Given a geocode response, functions mp_get_points
and mp_get_bounds
can be used to obtain geocoded locations as a point or polygon (bounds) layer.
The fourth function mp_map
is used to access the Maps Static API. It returns a stars
raster RGB image, which can be used as background in maps.
The CRAN version can be installed with:
install.packages("mapsapi")
The development version can be installed using remotes
:
install.packages("remotes") remotes::install_github("michaeldorman/mapsapi")
Once installed, the package can be loaded with library
:
library(mapsapi)
Note: due to new Google Maps API policy, starting from June 2018 the functions require an API key.
key = "AIz....."
The complete documentation can be found at https://michaeldorman.github.io/mapsapi/.
The following code section obtains (and plots) the driving directions from New-York to Los Angeles.
key = readLines("~/key")
# Get routes (XML document) doc = mp_directions( origin = "New-York", destination = "Los Angeles", alternatives = TRUE, key = key, quiet = TRUE ) # Extract lines 'sf' layer r = mp_get_routes(doc) # Plot library(maps) library(sf) map("state", fill = FALSE, col = "grey") plot(st_geometry(r), col = c("red", "green", "blue"), add = TRUE)
x = list.files(pattern = "^README-.*\\.png$") file.copy(x, "docs/", overwrite = TRUE)
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