Abstract: The invention relates to a method of reconstructing a surface topology of a surface (1) of an object (2). Conventional methods such as interferometry, or methods which acquire measurement values which represent slopes of the surface profile (slope values), show only a limited height resolution in the case of large flat objects such as wafers. In order to overcome this problem the surface of the object is sub-divided into smaller areas, and from each area slope values are obtained at optimum apparatus parameters. Then the areas are stitched together and the 3D topography is reconstructed.