The goal of this study was a better understanding of the quality of Volunteered Geographic Information (VGI), and by extension its utility. The research focused on the applicability of OpenStreetMap (OSM) building data for official spatial databases. In terms of feature completeness, the achieved results are in-line with other similar studies. The study concluded that in town centres the completeness of OSM data is relatively high but decreases further away from urban centres. It demonstrated that attribute completeness also relies on the level of urbanization as well as the nature of attribute. Furthermore, a very high overall positional accuracy was determined for OSM building data that ranged between 0.6 m in urban areas and 1.7 m in rural areas. This result is more than five times better than the frequently cited OSM accuracy results obtained by Haklay in 2010. In this work, a novel tool is introduced to help assess the completeness of OSM building-tagged features. The proposed index, called the matching feature area-based completeness, estimates the completeness of any areal feature set. This index is also flexible because it is neither affected by discrepancies in the feature outline modelling nor by the degree of abstraction. In addition, the author proposed a simple method to update the official register using the large volume of OSM building data “over-completeness” together with the building data excess indicator.

Key words: quality, spatial data, data completeness, OpenStreetMap, volunteered geographic information