A disclosed identification method of identifying a data point distribution area on a coordinate plane includes selecting a data point as a first representative point, setting the first representative point as an initial reference point, setting a direction passing through the initial reference point as an initial representative point selection direction, selecting an initial data point direction having a smallest angle relative to the initial representative point selection direction in a predetermined rotation direction when viewed from the initial representative point selection direction, selecting a data point corresponding to the initial data point direction as a second representative point of the data point distribution area, and determining whether there is an overlapping area where a distribution representative point area overlaps a determination area.