1. A method of generating a calibration database in a communications network comprising the steps of: (a) generating a grid of geographic locations to cover a region in a communications network having a plurality of cellular sites; (b) generating a set of network measurement reports (NMRs) for the region, the NMR being a collection of measurement parameters observed at selected geographic locations in the grid; (c) generating a label representing a first measurement parameter observed from ones of the plural cellular sites at one of the selected geographic locations, the label including a relative ranking by cellular site of the first measurement parameter; and (d) populating a calibration database for the communications network using the generated label, wherein at least two rankings of sites in the label are of equal rank, and dividing the label having equal ranked sites into two columns, each of the two columns having the same ranking of respective sites but with the two equal ranking sites transposed in the two columns.