1. A system for agricultural monitoring and prediction, said system comprising: a first reporting agent configured for reporting aerial data representing relative measurements of an agricultural metric in a geographic area, the relative measurements having an unknown bias; a second reporting agent configured for reporting ground-based data representing absolute measurements of the agricultural metric for a portion of the geographic area; and a database configured for storing said ground-based data and said aerial data along with other farming data for a wide geographic area; and a processor configured for accessing the database and using said ground-based data for the portion of said geographic area to calibrate said aerial data, thereby synthesizing absolute measurements of the agricultural metric for said geographic area from said aerial data.