Recent advances in technology have greatly transformed how geographic information is produced and have led to the phenomenon of Volunteered Geographic Information (VGI). VGI allows people with little geographical knowledge to contribute in the creation of maps and other kinds of geographic information. Because VGI is gathered by individuals who often have no formal training, the credibility and reliability of VGI is challenging. In this paper, we study what kinds of things might contribute to an assessment of the trustworthiness of data and the reputation of contributors in a VGI system. We present a model for analysing these characteristics and a method for automatically creating trustworthiness and reputation scores in order to assess the quality of VGI features.