A new technique for Scanning Electron Microscopy (SEM), which provides a mesoscopic coordinate system inscribed on the surface of the center of a tension test specimen has been proposed. Such technique allows to establish in a repeatable way any angle relative to any axis of any coordinate system, or distances between grains, or to measure local or global true deformation in parallel or perpendicular directions relatives to the tension axis. The application of such technique for a Zn-20.2%Al - 1.8% Cu alloy tension test specimen with a total length between shoulders of 412 mum length and a gage length of 371 mum, deformed at room temperature, allows to obtain: The mapping of the granular flow during superplastic deformation; this result is in qualitative agreement with similar flow-diagrams obtained previously by Ashby and Verral (Acta Metall. 21, 1973, p. 149) from their oil-emulsion model.