1. A method for performing spatial signature analysis, the method comprising: analyzing wafer defect density maps of multiple resolutions to identify one or more zones of interest on each of the wafer defect density maps, the wafer defect density maps (i) including a first wafer defect density map at a first resolution and a second wafer defect density map at a second resolution, the first resolution being different than the second resolution, and (ii) being derived from a defect map obtained by an inspection tool; and generating spatial signatures in response to relations between zones of interest corresponding to different ones of the wafer defect density maps; analyzing multiple groups of wafer defect density maps of multiple resolutions to identify the zones of interest, different ones of the groups obtained under different inspection conditions; generating, for each of the groups, spatial signatures in response to relations between the zones of interest and density of defects within the zones of interest; and selecting at least one inspection condition to be applied during an inspection process in response to a comparison between spatial signatures associated with each of the groups.