Assessing the positional accuracy of perceptual landscape data : a study from Friuli Venezia Giulia, Italy

Online GIS-based applications that combine mapping and public participation to collect citizens' voices on their surrounding environment are a way to collect original spatial data that do not already figure in authoritative data sets. However, these applications, relying on non-expert users, might produce spatial data of insufficient quality for the purpose for which they are collected. This article presents an approach for assessing the positional accuracy of vague landscape features, using the results from a map-based survey completed by a group of volunteers in the Friuli Venezia Giulia region of Italy. The spatial section of the survey, gathering both georeferenced data and textual information on the mapping activity, allows the assessment of whether there is a correspondence between the mapped features and the intended map locations. The findings reveal a greater accuracy among participants in completing the mapping activity relating to degraded sites than to those of beauty.