HEXAGON satellite image of Vietnam War bomb craters

A HEXAGON satellite image from the Quang Tri province of Vietnam shows numerous bomb craters. Declassified in 2011, HEXAGON, also named KH-9, provided imagery from 1971 to 1984. This image was acquired on March 20, 1973. University of Edinburgh researcher Philipp Barthelme developed machine learning methods to automatically detect bomb craters in this and other images. Barthelme’s method can help narrow down where to search for unexploded weapons. HEXAGON satellite imagery is archived at the USGS Earth Resources Observation and Science (EROS) Center.