Foody, G. M., See, L., Fritz, S., van der Velde, M., Perger, C., Schill, C., Boyd, D., & Comber, A. (2015). Accurate attribute mapping from volunteered geographic information: issues of volunteer quantity and quality. Cartographic Journal, 52(4), https://doi.org/10.1080/00087041.2015.1108658