 Tidal flats are a major natural feature of the ocean, occupying about 88% of the Earth's surface. They are also important for protecting coastal areas from coastal erosion and sea level rise. We developed a method to map the tidal flats using a 3D seismic model. This method allows for a large area of coastline to be covered in tidal flats without requiring the use of a geospatial database. The resulting maps show that the tidal flats are shaped by millions of individual wave-driven ROS waves and can respond to changes in sea level quickly. This article was authored by Richard O'Foller, Robert S. Clemens, Stuart R. Finn and others.