Impedance spectroscopy in a potentiostatic three-electrode configuration is extended to spatially resolved surface analysis with a resolution of about 10 mum, which is interesting for very many technical systems. Dot-by-dot experiments or complete surface scans to yield impedance images are presented. Examples of technical applications are the investigation of defects in CrNx hard coatings on Mg alloys, the grain dependent passivation of polycrystalline metals, and structuring of ultrathin Al films.