It is tempting to think that Linus’s Law can be applied to quality assurance for VGI. Mooney (2011) has examined patterns of editing of OpenStreetMap content, and has even found instances of “tag wars” in which the type associated with a feature is repeatedly changed by pairs of contributors who disagree on the correct type. In another study of OpenStreetMap, Haklay et al. (2010) have shown that positional accuracy of a feature improves as the number of editors increases, but no further improvement is evident when the number of editors exceeds 13.
In principle one might expect Linus’s Law to apply to VGI. But in practice its reliance on multiple “eyes” suggests that it will apply best to geographic facts that are prominent, and less well for facts that are obscure. A fact might be obscure because it refers to a location in a sparsely populated or under-explored part of the world, or because it persists for only a short period of time, or because it refers to a property Z that interests few people. Consider, for example, the case shown in Fig. 1, which depicts an area in Goleta, California. Wikimapia (www.wikimapia.org) is a project to “describe the whole world” by identifying and providing detailed descriptions of point or area features. At time of writing over 17 million features had been located and described. Wikimapia is in effect a crowd-sourced gazetteer (Goodchild and Hill, 2008), a catalog of placenames, geographic locations, and feature descriptions.