Volunteered geographic information

Volunteered geographic information (VGI) is the harnessing of tools to create, assemble, and disseminate geographic data provided voluntarily by individuals (Goodchild, 2007). VGI is a special case of the larger Web phenomenon known as user-generated content. Some examples of this phenomenon are , OpenStreetMap, and Google Map Maker. VGI can also be seen as an extension of critical and participatory approaches to geographic information systems. VGI attracted concerns about data quality, and specifically about its credibility and the possibility of vandalism. These sites provide general base map information and allow users to create their own content by marking locations where various events occurred or certain features exist, but aren’t already shown on the base map.

One of the most important elements of VGI in contrast to standard UGC is the geographic element, and its relationship with collaborative mapping. The information volunteered by the individual is linked to a specific geographic region. While this is often taken to relate to elements of traditional cartography, VGI offers the possibility of including subjective, emotional, or other non-cartographic information. Geo-referenced data produced within services such as Trip Advisor, Flickr, Twitter and Panoramio can be considered as VGI.

The term VGI has been criticized for poorly representing common variations in the data of OpenStreetMap and other sites: that some of the data is paid, in the case of CloudMade's ambassadors, or generated by another entity, as in US Census data. Because it is gathered by individuals with no formal training, the quality and reliability of VGI is a topic of much debate. Some methods of quality assurance have been tested, namely, the use of control data to verify VGI accuracy.

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