A system and method for using location data from actual 911 cell phone calls, to determine the coverage areas (orientation and range) of any sector (antenna) in a cell phone system. This coverage area is typically described as the area enclosed by a circular sector with the antenna at the center of the circle. The physical locations of the actually received 911 cell phone calls are determined with respect to the physical location of the antenna. These locations are typically defined in terms of latitude and longitude. A percentage of locations of the origins of the cell phone calls that is desired to be captured by the area enclosed by the circular sector are determined. Two variables are used to adjust the capture of the desired number of calls—the length of the arc (expressed in terms of the percentage of phone calls enclosed by a given length) and the radius of the circle (range of the antenna) (again expressed in terms of the percentage of calls enclosed by the resulting area). The purported coverage area of the antenna is received from the cell phone service provider. The actual determined coverage area (including the locations of received calls) and the purported coverage area can be graphically represented on a single output. This output can be used by various agencies to determine the proper routing of future emergency 911 cell phone calls to Public Safety Answering Points (PSAP) to assist them in determining how cell phone calls to the antenna should be routed.