Abstract: A prescription farming control system includes a navigation controller and a product delivery controller for controlling the rate of operation of a number of agricultural product delivery mechanisms mounted on an applicator vehicle as a function of the global position of the vehicle in an agricultural field. Information is stored in computer memory on board the vehicle to define a number of layers corresponding to each of the delivery mechanisms, each layer defined by a number of polygons representing different levels of activity of the corresponding mechanism. Each polygon is defined by a plurality of vertices. In one approach, line segments between adjacent vertices defining each polygon for each layer are evaluated based on crossings of global coordinate axes passing through the vehicle position to determine whether the vehicle position falls within the particular polygon.

Abstract: A prescription farming control system includes a navigation controller and a product delivery controller for controlling the rate of operation of a number of agricultural product delivery mechanisms mounted on an applicator vehicle as a function of the global position of the vehicle in an agricultural field. Information is stored in computer memory on board the vehicle to define a number of layers corresponding to each of the delivery mechanisms, each layer including a number of zones representing different levels of activity of the corresponding mechanism. Each zone is defined by a plurality of vertices, rather than on a pixel-by-pixel basis. The navigation controller receives satellite positioning data to combine with pseudorange correction data received from a fixed ground station to determine a corrected accurate global position of the vehicle. A graphics coprocessor includes active invisible graphics memory page onto which each layer is sequentially drawn and interrogated.