Unmanned underwater vehicles utilize seafloor mapping, bathymetry, digital cameras, magnetic sensors, and ultrasonic imaging. Some globes have surface texture showing topography or bathymetry. The Simrad EM300 multibeam side-scanning sonar system collected bathymetry and backscatter data. Multibeam data includes bathymetry, acoustic backscatter, and water column data. The bathymetry of the seafloor favoured the development of large surfing-type tsunami waves. Multibeam systems acquire both bathymetry (depth) and backscatter (intensity) data. The global bathymetry is sometimes combined with topography data to yield a Global Relief Model. When land topography and bathymetry is combined, a truly global relief model is obtained. Today, the UKHO has expertise in areas such as bathymetry, oceanography, geodesy and data science. Changes in bathymetry can affect the strength of an upwelling. Video analysis gives coastal zone managers the opportunity to obtain bathymetry. The peculiar ocean bathymetry off Nazare is largely responsible for the very large wave faces. The MR1 is full-ocean-depth capable, and provides both bathymetry and sidescan data. Starting in the early 1930s, single-beam sounders were used to make bathymetry maps. When relief is described underwater, the term bathymetry is used.