Nominatim Cookbook

This page collects tutorials and howtos around customizing your installation and using the Nominatim API in unexpected ways.

Do you have used Nominatim in new and unexpected ways and want to share a tutorial? Please post it in the Nominatim Discussion under Show&Tell.

Customizing Nominatim

Building your own transliterations

Nominatim transliterates all scripts to Latin to make sure that search works across different scripts. The standard transliteration does not work for all languages equally well. This tutorial shows how to add custom transliterations for selected areas of the world using the example of Cantonese in Hongkong.

Talks and presentations

Boundaries, Places and the Future of Tagging (EN)

2021-09-21 at State of the Map

One of the fundamental steps of preparing OSM data for searching is the extraction of information about their location, commonly known as their address. This is not a simple task because OSM data is much less structured than traditional databases and many users revert to using external data for this reason. However, the data is there and should therefore be usable. In the course of the last year the address algorithm of Nominatim received a major overhaul to improve how addresses are generated from OpenStreetMap data.

The first part of the talk introduces the new algorithm and how it came to be. We’ll look into the current state of tagging of boundaries, the problem of the urban/rural divide and the difficulties of country-specific mapping.

The second part of the talk deals with the more general question what the evolving tagging schema of the OpenStreetMap database means for data users. The free-form tagging is one of the big strengths of OpenStreetMap. But the lack of rules does not necessarily have to mean lack of order. Using the example of address extraction, I’d like to discuss the future of the tagging schema from the point of view of a data user.

Finding places: an introduction to Nominatim (EN)

2021-04-23 at CodeOp

This talk dives into the details of Nominatim, looking into both the general architecture of the software and the design decisions behind it, as well as the specific challenges of searching through a huge geographical database. We’ll close with some insights into practical aspects of open-source development and advice on how to get involved.

Nominatim für den Hausgebrauch (DE)

2021-06-07 at FossGIS conference

In den letzten Jahren hat sich viel getan, um die Installation von Nominatim einfacher zu machen. In dieser Demo-Session zeige ich, wie man in nur 20 Minuten seinen eigene Installation von Nominatim aufsetzen, Daten einer Region importieren und eine erste Liste von Adressen geocodieren kann.

Customizing Search for Special-Interest Maps (EN)

2019-09-22 at State of the Map

This talk explores ways to improve the search experience for special-interest maps. We start with simple approaches to boost results using existing web APIs and then look into different ways for creating a small custom domain-specific search engine. We discuss advantages and disadvantages of the different approaches and show common pitfalls for implementations. Although some knowledge in system administration and programming is expected, the focus is on solutions for small and medium projects that are realized with limited resources.

Addressing addresses (EN)

2018-07-28 at State of the Map

We are all used to describe locations with words. The concept is universally known as addresses. You put them on postcards and letters and expect that you find the right places on the map when you put them in the search box on For a computer this can be surprisingly challenging because addresses can take many shapes and forms in different regions of the world. This talk looks into different address formats in the real world, the different ways addresses can be tagged in OSM and how they can be efficiently processed.

Nominatim: Behind the scenes (EN)

2013-09-08 at State of the Map

This talk takes a look inside OSM’s main search engine. It explains how the raw OSM data is processed into a huge address database and how a search query is turned into the right answer (or not on some occasions). The focus is less on the technical details but more on the general principles, clearing up some of the mysteries and misconceptions around Nominatim, helping the interested mapper to better understand how their carefully mapped areas are turned into something that can be found by others.

Der OpenStreetMap-Geocoder Nominatim (DE)

2013-06-14 at FossGIS conference

Dieser Vortrag gibt einen kurzen Einblick ins Innere von Nominatim. Es wird erklärt, wie die OSM-Daten vorverarbeiten werden, wie ein Ort seine Adresse erhält und wie schlussendlich die Suche selber funktioniert. Der Schwerpunkt liegt dabei weniger auf technischen Details sondern der Vortrag wird mehr die grundlegenden Prinzipien erklären, die der Suche zugrunde liegen. Damit soll dem interessierten Mapper geholfen werden, besser zu verstehen, wie die sorgfältig in OSM erfassten Daten verarbeitet werden, damit sie von anderen gefunden werden können.