Seafloor topography, or bathymetry, has significant economic, military, and scientific research value. High-precision seafloor topographic data are helpful for studying the geographic features of the seafloor and the structure of the Earth's crust. Moreover, the seafloor requires detailed mapping to ensure fairway safety and aid in submarine navigation.Echo sounding techniques have been classically used for mapping the seafloor. From single-beam sounding in the 1950s to multibeam sounding in the 1980s , echo sounding techniques have advanced from point measurement to surface measurement. However, it is still a difficult task to obtain global seafloor topography with traditional methods within a short period (Carron et al., 2001;Sandwell & Smith, 2001). Fortunately, with the improvements in the accuracy and density of satellite altimetry data, using gravity anomalies (GAs) obtained from altimetry data to predict depth has become a feasible approach. Dixon et al. (1983) were among the first researchers to use SEASAT altimetry data to predict depth. Sandwell (1994, 1997) used GAs to construct a global seafloor model and exceedingly filled in the blank areas in nautical charts. Since then, a growing number of global seafloor models have been released, such as ETOPO1 (