1. A method of determining a localized measure of regional pattern density in a fabrication process of a chip, the method comprising: determining pattern density values for each cell of a plurality of cells of interest; averaging the pattern density values for each cell within a first selected region about and including a target cell to determine the localized measure of regional pattern density for the target cell; storing the localized measure of regional pattern density for the target cell; and repeating the averaging and the storing for each of the plurality of cells.