Understanding the dynamics of knowledge diffusion has profound theoretical and practical implications across a wide variety of domains, ranging from scientific disciplines to education and understanding emergent social phenomena. On the other hand, it involves many challenging issues due to the inherited complexity of knowledge diffusion. In this article, we describe a unifying framework that is designed to facilitate the study of knowledge diffusion through multiple geospatial and semantic perspectives. In particular, we address the role of intrinsic and extrinsic geospatial properties of underlying phenomena in understanding conceptual and geospatial diffusion of knowledge. We illustrate the use of visualizations of geographic distributions of terrorist incidents, the structural evolution of research networks on terrorism and avian flu, and concept-location relations extracted from news stories.