mapsapi

mapsapi provides an interface to the Google Maps APIs, currently three of them -

• Google Maps Direction API
• Google Maps Distance Matrix API
• Google Maps Geocode API

Functions mp_directions, mp_matrix and mp_geocode are used to access the APIs. 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.

Installation

You can install mapsapi from CRAN with -

install.packages("mapsapi")

Or from GitHub with -

# install.packages("devtools")
devtools::install_github("michaeldorman/mapsapi")

Example

The following code section obtains (and plots) the driving directions from New-York to Los Angeles.

Note: due to new Google Maps API policy, starting from June 2018 the functions require an API key.

library(mapsapi)

# Google API key
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)
#> Linking to GEOS 3.6.2, GDAL 2.2.3, PROJ 4.9.3

map("state", fill = FALSE, col = "grey")
plot(st_geometry(r), col = c("red", "green", "blue"), add = TRUE)