Crowdsourced and Open-Source Mapping

For most of its history, authoritative mapmaking was the preserve of national mapping agencies and commercial map publishers, but the early 21st century saw the rise of crowdsourced, editable mapping built on contributions from ordinary volunteers rather than professional surveyors. OpenStreetMap (OSM), founded in the United Kingdom in 2004 by Steve Coast, was created partly in response to the restrictive licensing terms then attached to the UK's Ordnance Survey mapping data, and it adopted a wiki-style editing model in which any registered user can add or correct map features using GPS traces, aerial imagery, or direct local knowledge, with all resulting data released under an open license (currently the Open Database License). Geographer Michael Goodchild coined the term "volunteered geographic information" (VGI) in a widely cited 2007 paper, "Citizens as Sensors," published in GeoJournal, to describe this broader phenomenon of ordinary citizens acting, in effect, as a distributed network of geographic data-collection sensors.