the dryland cropping terrain the cut fill map 50 is shown in fig9 as a plan view and has two dimensional axes x 51 and y 52 the cut fill map 50 is commonly used in the industry and clearly shows which areas need to be lowered cut and which areas need to be raised filled a legend 53 is shown to indicate the amount of terrain that needs to be cut or filled to achieve the optimised terrain model 14 in this example as the dryland optimised terrain requires less earth moving the quantities of earth required to be cut fill are significantly less than were required for the cut fill map shown in fig5 the levelling surface 15 can be outputted to a three dimensional controller in land levelling machinery to achieve the desired optimised terrain model 14 it shall be appreciated that the present invention can output levelling surfaces that can minimise crop yield reductions earth moving required the costs to implement etc furthermore because there are generally less designer inputs and less trial and error than previous methods systems the present invention may allow a terrain designer with less skill than was previously required to produce an improved levelling surface in less time than was previously required it is to be understood that the terminology employed above is for the purpose of description and should not be regarded as limiting the foregoing embodiments are intended to be illustrative of the invention without limiting the scope thereof the invention is capable of being practised with various modifications.