Ranking of VGI contributor reputation using an evaluation-based weighted pagerank

The quality of volunteered geographic information (VGI) is questionable as it emerges through a diversity of contributors. The reputation of a contributor is increasingly applied to VGI quality assessment and its assurance. Research on how to measure and validate reputation, however, is still required. This study proposes an evaluation-based weighted PageRank (EWPR) algorithm to provide a ranking metric of reputation. Ranking is established on the basis of the assumptions that: (a) there is an evaluation relationship between VGI contributors; (b) the reputation of a contributor is movable within the VGI community; and (c) highly active contributors are more likely to have high reputation. By means of case studies using OpenStreetMap, two existing methods are compared with the EWPR algorithm. The results show that the algorithms used for web pages and social network participants are applicable to understand the reputation of VGI contributors. This study also applies credibility, based on reputation, as a popular indicator of VGI quality. The high correlation between credibility and VGI characteristics indicates that reputation is useful for dealing with quality variability in VGI.