Geocoding Services

Source: vignettes/geocoder_services.Rmd

Overview

The supported geocoding services are shown in the table below. The method is used to select the geocoding service in tidygeocoder functions such as geo() and reverse_geo(). The usage rate limitations are listed for the free tier of the service when applicable and many services have faster rates available with paid plans.

Also note that there are many other considerations when selecting a geocoding service such as if the service uses open source data with permissive licensing or if there are restrictions on how you can use the data provided by the service. Refer to each service’s documentation for details.

Service Method API Key Required Batch Geocoding Usage Limitations API Documentation
Nominatim osm 1 query per second docs
US Census census ✅ docs
ArcGIS arcgis docs
Geocodio geocodio ✅ ✅ 1000 queries per minute (free tier) docs
Location IQ iq ✅ 2 queries per second (free tier) docs
Google google ✅ 50 queries per second docs
OpenCage opencage ✅ 1 query per second (free tier) docs
Mapbox mapbox ✅ 600 queries per minute (free tier) docs
HERE here ✅ ✅ 5 queries per second (free tier) docs
TomTom tomtom ✅ ✅ 5 queries per second (free tier) docs
MapQuest mapquest ✅ ✅ docs
Bing bing ✅ ✅ docs
Geoapify geoapify ✅ 5 queries per second (free tier) docs

Highlights:

  • The US Census service does not support reverse geocoding and is limited to the United States.
  • Geocodio is limited to the United States and Canada.
  • The Census and Nominatim (“osm”) services are free and do not require an API key.
  • ArcGIS can be used for free without an API key, but some features require a paid subscription and API key.
  • Geoapify, Geocodio, Location IQ, OpenCage, Mapbox, HERE, TomTom, MapQuest, and Bing are commercial services that offer free tiers.
  • The Google service has no free tier and bills per query.

Other Notes:

  • The US Census service supports street-level addresses only (ie. “11 Wall St New York, NY” is OK but “New York, NY” is not).
  • The Mapbox service is capable of performing batch geocoding when using the permanent endpoint, but this capability is not currently implemented in tidygeocoder. If you’d like to add this capability to the package see issue #73.
  • The ArcGIS service is capable of performing batch geocoding but this capability is not currently implemented in tidygeocoder. If you’d like to add this capability see #102.
  • For the ArcGIS service, an API Key is not strictly required if the service is used for search capabilities only (see Free vs. paid operations). It is possible to include an API Key on the request via the custom_query parameter:
tidygeocoder::geo(address = "New York, USA", method = "arcgis",
  custom_query = list(token = "<API_KEY>"))

Usage Notes

  • When used in batch mode, the US Census geocoder will return NA data when there are multiple results available for an address. The expectation is that you would see that a “Tie” is indicated and use single address geocoding to return the results for these addresses. See #87 for details.
  • When performing reverse geocoding, the Mapbox service requires a types parameter to be set if limit > 1. See #104.
  • The Bing batch geocoder does not use the limit parameter (#106).

API Parameters

The api_parameter_reference maps the API parameters for each geocoding service to a common set of “generic” parameters. The generic_name below is the generic parameter name while the api_name is the parameter name for the specified geocoding service (method). Refer to ?api_parameter_reference for more details.

API Key Retrieval

API keys are retrieved from environmental variables. The name of the environmental variable used for each service is stored in the api_key_reference dataset. See ?api_key_reference.

method env_var
geocodio GEOCODIO_API_KEY
iq LOCATIONIQ_API_KEY
google GOOGLEGEOCODE_API_KEY
opencage OPENCAGE_KEY
mapbox MAPBOX_API_KEY
here HERE_API_KEY
tomtom TOMTOM_API_KEY
mapquest MAPQUEST_API_KEY
bing BINGMAPS_API_KEY
geoapify GEOAPIFY_KEY

Minimum Time Per Query

The minimum time (in seconds) required per query to comply with the usage limitations policies of each geocoding service is stored in the min_time_reference dataset. See ?min_time_reference.

method min_time description
osm 1.00 1 query per second
geocodio 0.06 1000 queries per minute (free tier)
iq 0.50 2 queries per second (free tier)
google 0.02 50 queries per second
opencage 1.00 1 query per second (free tier)
mapbox 0.10 600 queries per minute (free tier)
tomtom 0.20 5 queries per second (free tier)
here 0.20 5 queries per second (free tier)
geoapify 0.20 5 queries per second (free tier)

Links to the usage policies for each geocoding service:

Batch Query Size Limits

The maximum number of inputs (geographic coordinates or addresses) per batch query for each geocoding service is stored in the batch_limit_reference dataset. See ?batch_limit_reference.

method batch_limit
census 10,000
geocodio 10,000
tomtom 10,000
here 1,000,000
mapquest 100
bing 50