Analyzing the Spatial-Semantic Interaction of Points of Interest in Volunteered Geographic Information Christoph Mülligann 1 , Krzysztof Janowicz 2 , Mao Ye 3 , and Wang-Chien Lee 3 1 Institute for Geoinformatics, University of Münster, Germany cmuelligann@uni-muenster.de 2 Department of Geography, University of California, Santa Barbara, USA jano@geog.ucsb.edu 3 Department of Computer Science and Engineering, Pennsylvania State University, USA mxy177|wlee@cse.psu.edu Abstract. With the increasing success and commercial integration of Volunteered Geographic Information (VGI), the focus shifts away from coverage to data quality and homogeneity. Within the last years, several studies have been published analyzing the positional accuracy of fea- tures, completeness of specific attributes, or the topological consistency of line and polygon features. However, most of these studies do not take geographic feature types into account. This is for two reasons. First, and in contrast to street networks, choosing a reference set is difficult. Second, we lack the measures to quantify the degree of feature type mis- categorization. In this work, we present a methodology to analyze the spatial-semantic interaction of point features in Volunteered Geographic Information. Feature types in VGI can be considered special in both, the way they are formed and the way they are applied. Given that they re- flect community agreement more accurately than top-down approaches, we argue that they should be used as the primary basis for assessing spatial-semantic interaction. We present a case study on a spatial and semantic subset of OpenStreetMap, and introduce a novel semantic sim- ilarity measure based on the change history of OpenStreetMap elements. Our results set the stage for systems that assist VGI contributors in suggesting the types of new features, cleaning up existing data, and in- tegrating data from different sources. 1 Introduction The rise of Volunteered Geographic Information (VGI) as coined by Goodchild[1] is closely tied to projects such as OpenStreetMap (OSM) 1 or Wikimapia 2 . These projects provide open platforms for volunteers to contribute geographic data and make them accessible for others under an open license. Volunteered information 1 http://www.openstreetmap.org 2 http://wikimapia.org/