Thanks to advances in geosensing technologies, real-time data acquisition through sensors and imagery devices has been widely deployed with many applications. In addition to temporal information, in many cases such acquired data streams include information about geographical locations and/or spatial extents (such as point coordinates, lines, or polygons). While collecting such so-called “GeoStream” data has been a major propeller to advance the state of the art in geographic information systems, efficient and effective processing, analyzing, and mining GeoStream data pose many challenges. This workshop addresses the research communities in both stream processing and geographic information systems. It brings together experts in the field from academia, industry and research labs to discuss the lessons they have learned over the years, to demonstrate what they have achieved so far, and to plan for the future of geostreaming.