An initial model topography is obtained by taking the median value of all sea points in the etopo2 grid which lie under each grid cell of the ORCA1 grid. If 40% or more of the etopo gridcells are land, then the nemo point is set to land.
The program (etopo2nemo) also allows optional smoothing passes (which have not been used to date) and will remove any isolated surface bays (single sea points surrounded by land). It also assumes an F-point fold on the "Northern" boundary and East-West cyclic boundaries.
This simple algorithm produces a realistic model bathymetry over most of the ocean basins. It fails to preserve some narrow features which have to be hand edited at the next stage.