Methane mapping uses a fast, accurate, and easy-to-use methane measurement tool mounted in a vehicle to generate maps showing methane concentrations across an area. The tool measures methane at parts-per-billion resolution in seconds. Maps can help identify potential natural gas leaks and distinguish between natural and human-caused methane sources to target areas for further study. One example map showed a methane "ribbon" along the vehicle's path and a peak indicating a likely roadside source located using wind direction data.