Definitions of flow indicators are derived by adapting Edie's definitions through a stream-based approach and a data-driven spatio-temporal discretization framework. The stream-based approach accounts for the multidirectional nature of pedestrian flows. The data-driven discretization framework, based on three-dimensional Voronoi tessellations, accounts for the pedestrian heterogeneity in the case when only samples of points are available, instead of the analytical description of trajectories. The proposed approach enables the pedestrian flow characterization to be applicable to any space-time domain of interest.