利用Smyth & Sandwell地形资料，matlab中也有相关的函数为[latgrat,longrat,z] = satbath[latgrat,longrat,z] = satbath(scalefactor)[latgrat,longrat,z] = satbath(scalefactor,latlim,lonlim)[latgrat,longrat,z] = satbath(sc