The OLS Analog Derived Lightning dataset consists of global lightning signatures from the Defense Meteorological Satellite Program (DMSP) Operational Linescan System (OLS) that have been analyzed from filmstrip imagery. These signatures show up as horizontal streaks on the film images. The location of each of these streaks has been digitized in order to develop a preliminary database of global lightning activity. Monthly HDF data files are available for June and July 1973; Sept. - Dec. 1977; Jan. - Aug. 1978; Jan. - Dec. 1986; Jan. - Oct. 1987; Dec. 1988; Jan. - Dec. 1990; and Jan. - Dec. 1991.