Tidygeocoder v1.0.3 is released on CRAN! This release adds support for reverse geocoding (geocoding geographic coordinates) and 7 new geocoder services: OpenCage, HERE, Mapbox, MapQuest, TomTom, Bing, and ArcGIS. Refer to the geocoder services page for information on all the supported geocoder services.

Big thanks go to Diego Hernangómez and Daniel Possenriede for their work on this release. You can refer to the changelog for the details on the changes in the release.

Reverse Geocoding

In this example we’ll randomly sample coordinates in Madrid and label them on a map. The coordinates are placed in a dataframe and reverse geocoded with the reverse_geocode() function. The Nominatim (“osm”) geocoder service is used and several API parameters are passed via the custom_query argument to request additional columns of data from Nominatim. Refer to Nominatim’s API documentation for more information on these parameters.

library(tidyverse, warn.conflicts = FALSE)
library(tidygeocoder)
library(knitr)
library(leaflet)
library(glue)
library(htmltools)

num_coords <- 25 # number of coordinates
set.seed(103) # for reproducibility

# latitude and longitude bounds
lat_limits <- c(40.40857, 40.42585)
long_limits <- c(-3.72472, -3.66983)

# randomly sample latitudes and longitude values
random_lats <- runif(
  num_coords, 
  min = lat_limits[1], 
  max = lat_limits[2]
  )

random_longs <- runif(
  num_coords, 
  min = long_limits[1], 
  max = long_limits[2]
  )

# Reverse geocode the coordinates
# the speed of the query is limited to 1 coordinate per second to comply
# with Nominatim's usage policies
madrid <- reverse_geo(
              lat = random_lats, random_longs, 
              method = 'osm', full_results = TRUE,
              custom_query = list(extratags = 1, addressdetails = 1, namedetails = 1)
          )

After geocoding our coordinates, we can construct HTML labels with the data returned from Nominatim and display these locations on a leaflet map.

# Create html labels
# https://rstudio.github.io/leaflet/popups.html
madrid_labelled <- madrid %>%
  transmute(
    lat, 
    long, 
    label = str_c(
        ifelse(is.na(name), "", glue("<b>Name</b>: {name}</br>")),
        ifelse(is.na(suburb), "", glue("<b>Suburb</b>: {suburb}</br>")),
        ifelse(is.na(quarter), "", glue("<b>Quarter</b>: {quarter}")),
        sep = ''
    ) %>% lapply(htmltools::HTML)
  )

# Make the leaflet map
madrid_labelled %>% 
  leaflet(width = "100%", options = leafletOptions(attributionControl = FALSE)) %>%
  setView(lng = mean(madrid$long), lat = mean(madrid$lat), zoom = 14) %>%
  # Map Backgrounds
  # https://leaflet-extras.github.io/leaflet-providers/preview/
  addProviderTiles(providers$Stamen.Terrain, group = "Terrain") %>%
  addProviderTiles(providers$OpenRailwayMap, group = "Rail") %>%
  addProviderTiles(providers$Esri.WorldImagery, group = "Satellite") %>%
  addTiles(group = "OSM") %>%
  # Add Markers
  addMarkers(
    labelOptions = labelOptions(noHide = F), lng = ~long, lat = ~lat,
    label = ~label,
    group = "Random Locations"
  ) %>%
  # Map Control Options
  addLayersControl(
    baseGroups = c("OSM", "Terrain", "Satellite", "Rail"),
    overlayGroups = c("Random Locations"),
    options = layersControlOptions(collapsed = TRUE)
  )

Limits

This release also improves support for returning multiple results per input with the limit argument. Consider this batch query with the US Census geocoder:

tie_addresses <- tibble::tribble(
  ~res_street_address, ~res_city_desc, ~state_cd, ~zip_code,
  "624 W DAVIS ST   #1D",   "BURLINGTON", "NC",  27215,
  "201 E CENTER ST   #268", "MEBANE",     "NC",  27302,
  "7833  WOLFE LN",         "SNOW CAMP",  "NC",  27349,
)

tg_batch <- tie_addresses %>%
  geocode(
    street = res_street_address,
    city = res_city_desc,
    state = state_cd,
    postalcode = zip_code,
    method = 'census', 
    full_results = TRUE
  )

You can see NA results are returned and the match_indicator column indicates a “Tie”. This is what the US Census batch geocoder returns when multiple results are available for each input address (see issue #87 for more details).

Too see all available results for these addresses, you will need to use mode to force single address (not batch) geocoding and limit > 1. The return_input argument (new in this release) has to be set to FALSE to allow limit to be set to a value other than 1. See the geocode() function documentation for details.

tg_single <- tie_addresses %>%
  geocode(
    street = res_street_address,
    city = res_city_desc,
    state = state_cd,
    postalcode = zip_code,
    limit = 100,
    return_input = FALSE,
    method = 'census', 
    mode = 'single',
    full_results = TRUE
  )

We can now see there are two available results for each address. Note that this particular issue with “Tie” batch results is specific to the US Census geocoder service. Refer to the api_parameter_reference documentation for more details on the limit parameter.

The limit parameter can also be used to return all matches for a more general query:

paris <- geo('Paris', method = 'opencage', full_results = TRUE, limit = 10)

The RMarkdown file that generated this post is available here.