Taginfo, a project by Jochen Topf, has been a huge element in making iD great for editing and learning about OpenStreetMap’s tag system.

Many of the most important features in iD are here because of the hard work of others in the community: the OSM API, OpenStreetMap US’s TIGER 2012 layer, algorithms pioneered in Potlatch 2 and JOSM, and much more.

Taginfo is written in a smart style - a C++ parser for wiki & OSM Planet using Jochen’s own osmium framework, combined with a simple sinatra-based web frontend. This means that it’s fast in practice, and a service that we’ve grown to rely on.

The Taginfo API is extensive: it even generates maps of worldwide tag usage, to find region-specific patterns. Here’s a map of the distribution of the highway= key.

We first started using Taginfo to power autocomplete functionality in iD: given a key, we can show popular values, and even filter through these values so that keys with many different values, like name, don’t have confusing autocomplete suggestions.

To take this concept even further, we’re using Taginfo’s wiki_pages API to bring in deeper documentation for specific tag combinations, informing users of particulars like whether a specific road type matches up with highway=motorway_link or how to tag a cycleway.

We’re able to include images from wiki pages because of a new version of the API which Jochen kindly developed with iD in mind.

Taginfo has been a great resource and enables iD to provide a critical improvement to conventional tagging interfaces: tags are still entered through an unlimited freeform, but more useful context around common choices is provided as guidance for both, new and experienced mappers.

Devlogging work on the OpenStreetMap project by the MapBox team.

Much of this work is currently focused on improvements to OpenStreetMap funded by the Knight Foundation

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