Division of rice yield estimation by remote sensing in Hunan Province based on spatial analysis and two-dimension graphics cluster methods

In order to improve the accuracy of rice yield estimation by remote sensing, division of rice area in Hunan Province was studied based on rice cropping systems and topographic feature. Rice cropping systems, the ratio between rice area and land, rice unit yield at the county level, topographic feature, and location for each county were selected as the districting factors, and the methods of spatial analysis and two-dimension graphics cluster were developed. The results show two first-grade divisions, including single and double rice division, and five second-grade divisions, two of them belong to single rice division, and others belong to double rice division. These divisions keep the spatial continuation and the administrative district integrity, and the natural economy conditions uniformity inside division. Rice cropping systems, rice unit yield, and topographic feature had the independence between each division. These properties of division are helpful to estimation of rice yield by remote sensing.