Fig. 2

A Dishes in a plant field can be referred by a natural coordinate system with x-axis toward the East, y-axis toward the North and z-axis showing the altitude. The built-in sun tracking system of each dish ensures that all dishes face toward the sun. The shade area would only be the regions where dishes overlap along the projection of sun radiation. B A local (dish) coordinate (\(x'-y'-z'\)) with \(z'\)-axis pointing at the sun (red-filled dot, described by its azimuth angle \(\phi\) and elevation angle \(\theta\)) is originated at the dish. Neighboring dishes shading to it would only be those with \(z'\) values larger than 0