Boundaries, Places and the Future of Tagging

Room: Track 1 - Talks

Friday, 15:45 UTC
Duration: 20 minutes (plus Q&A)


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  • Sarah Hoffmann

Nominatim is the search engine that powers the search box on the main OSM site. 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.