... If set, it will transform a gridded data set from a rectangular coordinate system onto a geographical system by resampling the surface at the new nodes. If not set, it will project a geographical gridded data set onto a rectangular grid. ... The new node spacing may be determined in one of several ways by specifying the grid spacing, number of nodes, or resolution. ... D Set the grid spacing for the new grid. ... N Set the number of grid nodes in the new grid. ...