Method and apparatus for prescription application of products to an agricultural field

A control system for controlling functional components of a vehicle in relation to its position over a tract of land, each of the functional components capable of controllable levels of activity and having a device controller which controls the operation of the corresponding component in response to control signals derived in accordance with a predetermined program of operation, the control system comprising:

• for each of the functional components, a digital map stored in a memory, the map defining a number of zones, each zone corresponding to a predetermined level of activity of the corresponding functional component;
• navigation means for determining the global position of the vehicle as the vehicle moves over the tract of land;
• a computer receiving the global position as an input and operable on the digital map corresponding to each of the functional components to identify which of the number of zones corresponds to the global position of the vehicle, said computer further operable to generate a control signal to the device controller for each of the functional components corresponding to said predetermined level of activity for the identified zone,
• wherein each of said number of zones is a polygon defined by a plurality of vertices, with the global position of only the vertices stored in said memory;
• and
• wherein said computer implements a software routine operable to evaluate the global position of the vehicle relative to the plurality of vertices defining a polygon to determine whether the vehicle global position falls within said polygon.

A method for variably controlling functional components of a vehicle in relation to its position over a tract of land, each of the functional components capable of controllable levels of activity in response to control signals derived in accordance with a predetermined program of operation, comprising the steps of:

• storing a digital map for each of the functional components defining a number of zones corresponding to a predetermined level of activity of the functional component, each zone defined by a plurality of vertices and line segments between successive vertices;
• determining the global position of the vehicle as it moves over the tract of land;
• evaluating the global position relative to the line segments defining the digital map for each of the functional components to identify in which zone of each map the global position of the vehicle falls;
• and
• issuing control signals to each of the functional components in relation to the predetermined level of activity for the identified zone of each map.