A method for making a land management decision comprises surveying a field with a location-determining receiver to determine position data and corresponding elevation data. A data processor or elevation module determines an average elevation data for a zone within the field around a particular cell. The data processor or classifier classifies each cell into classifications comprising a depression cell and a summit cell based on the determined elevation difference between the particular cell and the average elevation. The data processor and the prescription module generate a prescription for the cells in the field based on at least one of the classification and the determined elevation difference.