1) For idealistic cartesian cases - providing dx, dy and nx, ny
2) Reading from a bathymetry file the natural information to provide is the coordinates of the T points - where you have the depth values and then calculate dx, dy + x, y, dx, dy for the U, V and X grids - this will work for both cartesian and spherical grids
3) For curvilinear grids the cell faces must be provided. This makes specification of U,V and X points straight forward
1) For idealistic cartesian cases - providing dx, dy and nx, ny
2) Reading from a bathymetry file the natural information to provide is the coordinates of the T points - where you have the depth values and then calculate dx, dy + x, y, dx, dy for the U, V and X grids - this will work for both cartesian and spherical grids
3) For curvilinear grids the cell faces must be provided. This makes specification of U,V and X points straight forward