Mapping fire perimeters is important work. It guides post-fire restoration efforts, fire mitigation strategies, and helps track of trends in burn severity over time. In the past, many of Canada’s fire agencies relied heavily on techniques like sketch mapping, which estimate burned area without exact measurements. In the pre-satellite era, pilots would sometimes fly over the edge of a fire while a passenger recorded its extent. On this episode of Eyes on Earth, we hear about what two researchers from Natural Resources Canada learned when they used Landsat satellite data to rebuild historical fire perimeters.