Data-based public art is an innovating new form of digital art which presence is increasing in the cities datascape. Data as a medium provides a special relationship with time and space by connecting the context of data mining to the one of its exhibition. The virtual component of data art opens an augmented space, where the different dimensions of data are mediated. This essay analyses how this new artform can contribute to a creative and digital placemaking of a city by offering a special sensory experience as well as renewing the storytelling of its space. Three case studies support the analysis. “Living connections”, projected on an emblematic bridge in Montreal, contributes to a spectacular placemaking. “Interconnected”, a data sculpture in Charlotte airport, relates to infrastructure placemaking. Finally, “Herald / Harbinger” connects the industrialized society with nature in a global connection. The results participate to the reflection on the nature and specificity of data art as well as enhancing its potential of transforming public space by engaging a specific relation with time, place and people.