Large data sets of linked geospatial data are progressively appearing on the web. It is a direct consequence of the intense research activity of recent years, which has consolidated concepts, models, and related technology. These data sets are increasing in number as well as in size, defining a trend that requires novel approaches and cutting-edge applications.

Geospatial information rarely reflects a static reality, as most of the time it represents contexts and phenomena in their evolution. Therefore, the temporal dimension of data can play a crucial role in the context of many applications. This paper deals with the spatiotemporal analysis of linked data. Sextant, the tool described in the paper, allows the browsing and the visualization of time-evolving linked geospatial data in a context of interoperability and flexibility.

The paper is interesting in all its parts. As a reader, I appreciate that the key concepts are introduced and clearly explained before going through technical details. Furthermore, the characteristics of the tool are clearly stated and future directions seem convincing. This is definitely an interesting contribution to the field.