A package with classes and methods for spatio-temporal data. In particular, space-time regular lattices, sparse lattices, and irregular data are supported, with limited support for trajectories, but not for topologies with S/T interactions such as space-time prisms. Utility functions are provided for plotting data as map sequences (lattice or animation) or multiple time series; for spatial and temporal selection, as well as methods for retrieving coordinates, for subsetting, print, summary, etc.