International Journal of Geo-Information Article Shared Data Sources in the Geographical Domain— A Classification Schema and Corresponding Visualization Techniques Franz-Benjamin Mocnik * , Christina Ludwig , A. Yair Grinberger , Clemens Jacobs, Carolin Klonner and Martin Raifer Institute of Geography, Heidelberg University, 69120 Heidelberg, Germany;
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[email protected] Received: 12 March 2019; Accepted: 15 May 2019; Published: 27 May 2019 Abstract: People share data in different ways. Many of them contribute on a voluntary basis, while others are unaware of their contribution. They have differing intentions, collaborate in different ways, and they contribute data about differing aspects. Shared Data Sources have been explored individually in the literature, in particular OpenStreetMap and Twitter, and some types of Shared Data Sources have widely been studied, such as Volunteered Geographic Information (VGI), Ambient Geographic Information (AGI), and Public Participation Geographic Information Systems (PPGIS). A thorough and systematic discussion of Shared Data Sources in their entirety is, however, still missing. For the purpose of establishing such a discussion, we introduce in this article a schema consisting of a number of dimensions for characterizing socially produced, maintained, and used ‘Shared Data Sources,’ as well as corresponding visualization techniques. Both the schema and the visualization techniques allow for a common characterization in order to set individual data sources into context and to identify clusters of Shared Data Sources with common characteristics.