Maps seem the most intuitive way to visualize massive urban data but they also raise some well-known graphical problems (such as visual clutter, etc.). This paper focuses on processing massive spatio-temporal data in order to ease multi-scale exploration. To this end, we describe a preprocessing tool that enables the automatic creation of a multi-resolution grid from a high resolution grid of spatio-temporal data in a format compatible with webmapping applications (vector tiles). The use of this tool is exemplified through a prototype that offers the possibility to navigate into a massive itinerary request dataset collected in the Ile-de-France region.