atlas with coordinates

Reverse Geocoding Resources

Learn more about reverse geocoding with open data

To be most useful, your reverse geocoder likely needs a lot of data. There are many sources for public domain data - as well as tools to make use of them. Using open data promotes accountability, transparency, and participation. It also gives you the most flexibility with how you can use your reverse geocoder.

Additional Resources for Learning about Reverse Geocoding

Throughout the guide we've discussed the basics of reverse geocoding and the various issues involved when building or buying a geocoding service. However, there is still much to learn. To further expand your geocoding and open data knowledge, here are some additional tools and resources:

Tutorials

We offer tutorials for using the OpenCage geocoding API with cut and paste code examples in over 30 different programing languages.

OpenCage geocoding API javascript tutorial

Podcasts

The Mapscaping podcast, a popular podcast focusing on geospatial technologies and trends, interviewed OpenCage co-founder, Ed Freyfogle . Ed explains what geocoding is and many of the challenges in providing a dependable geocoding API.

Ed also chatted with the First things First Iot Podcast about geocoding, particularly in the context of Internet of Things.

If podcasts about geo are your thing, you should subscribe to the Geomob podcast, which is co-hosted by Ed, and where we regularly interivew guests from across the industry.

Behind the API: Open Data Sources We Use at OpenCage

The OpenCage Geocoding API is the quickest way to get open data-powered reverse geocoding. We use many of the open data sources we highlight below. In addition, you'll find open source packages and developer utilities used in robust, scalable geocoding projects from within the community.

OpenCage diagram

Nominatim and OpenStreetMap

As we've discussed elsewhere in this guide, OpenStreetMap (OSM) is an incredibly important project, which drives a worldwide geo dataset built by millions of individual mappers. OpenCage is a member of the OSM Foundation and national OpenStreetMap chapters for the UK and Germany. OpenStreetMap offers fantastic resources for map builders and other geo-geeks.

Built by a community of mappers, OpenStreetMap's worldwide data is continuously updated. Anyone can use OpenStreetMap's always up-to-date data for any reason, as long as credit is given.

The most useful OSM project for reverse geocoding is Nominatim.

DataScienceToolkit

DataScienceToolkit is a collection of open data sets and open-source tools for data science. Wrapped in an easy-to-use REST/JSON API with command line, Python, and Javascript interfaces, DataScienceToolkit has ample data software pre-installed.

Flickr Shapefiles

The entire dataset of Flickr Shapefiles 1.0 is available as a single download under CC0 / Public Domain. That's continents, countries, states, cities, and even neighborhoods. Find interesting ways to use them yourself here.

Geonames

GeoNames is a geographical database that contains over eleven million place names in total, from every country in the world. This data is available for download free of charge (under CC-BY at geonames.org.

Natural Earth Data

Natural Earth offers ready-to-use map data. Cartographers no longer have to waste time sifting through confusing tangles of poorly attributed data to make clean, legible maps.

Built through a collaboration of many volunteers, Natural Earth is supported by NACIS (North American Cartographic Information Society). You may access Natural Earth's data, which is free for use in any type of project under Public Domain by visiting naturalearthdata.com.

Quattroshapes and Twofishes

Quattroshapes is a collection of place shapes from foursquare. The business recommendation engine uses the tool to ensure localized results. This dataset is used by another foursquare-born project, Twofishes This geocoder and reverse geocoder works at a city or neighborhood-level..

what3words

what3words simplifies how we talk about location. The app assigns each 3m square in the world a unique 3-word address. Three-word addresses are easier to say and share, plus they're as accurate as latitude and longitude coordinates. For example, ///filled.count.soap marks the exact entrance to what3words' London headquarters at 51.520847, -0.19552100.

what3words aims to become a global standard for communicating location. Experience the ease of finding tents at festivals, navigating to B&Bs, and directing emergency services to the right place when you use what3words.com.

Postcodes.io

As an open-sourced project under the OS OpenData license, Postcodes.io allows developers to search, reverse geocode, and extract UK postcodes and other data for free. Learn more at postcodes.io.

libpostal

Similarly, Libpostal is a C library for parsing/normalizing street addresses around the world. It does so with statistical NLP and open data to help users understand location-based strings in every language. We're proud to support the libpostal project financially with a monthly donation.

Yahoo Geoplanet

Though no longer provided by Yahoo, the company released its GeoPlanet dataset into Creative Commons. In particular, OpenCage uses its Whereonearth identifiers (WOEIDs), unique 32-bit numerical representations locations.

Addok

An address search engine, Addok works with Redis in the back-end. Addok imports and indexes data, serves a minimal API based on GeoJSON, reverse and batch geocodes, and more. As with all the tools behind the OpenCage API, Addok is open source, specifically under WTFPL license. Visit Addok's documentation for more information.

G-NAF and Canadian postcodes

G-NAF is Australia's Geocoded National Address File. A ubiquitous and powerful spatial dataset, G-NAF contains more than 13 million Australian physical address records, including geocodes. It's licensed ©PSMA Australia Limited licensed by the Commonwealth of Australia under the Open Geo-coded National Address File (G-NAF) End User Licence Agreement. Access G-NAF and more about its licensing here.

A crowdsourced dataset containing over 850,000 Canadian postal codes, Geocoder.ca's Canadian Postal Code Dataset is verified and geocoded to street level accuracy.

iana Time Zone Database

Available under Public Domain, the Internet Assigned Numbers Authority (iana)'s Time Zone Database contains code and data that represent the history of local time for many representative locations around the globe. The data is updated periodically to reflect changes made by political bodies to time zone boundaries, UTC offsets, and daylight-saving rules.

Mapzen Terrain Tiles

Finally, Mapzen Terrain Tiles provide basemap terrain coverage of the world in a raster tile format. Mapzen Terrain Tiles make it easier to process the data and build applications on top of it by aggregating, standardizing, and tiling multiple source datasets into common web mapping and desktop GIS formats and dimensions. Get more information about Mapzen Terrain Tiles here.

Learn more

To learn more about the open data sources we use, head over to our Credits and Sources page.

Need help with reverse geocoding?

At OpenCage we operate a highly-available, easy to use, affordable geocoding API built on open data, and used by hundreds of customers around the world. Learn more.