AN ADAPTED REGRESSION ESTIMATOR METHOD TO ASSESS THE CROP ACREAGE IN MENGCHENG COUNTY ON THE NORTH CHINA PLAIN

摘要

Image classifications including sub pixel analysis arernoften used to estimate directly the crop acreage, whilernground data collected during field surveys play arnsecondary role. This pixel counting approach often leadsrnto a biased estimation due to non-representative selectionrnof ground data and subjective a-priori knowledge ofrnanalysts. Instead regression estimator approachrncombining remote sensing information with a rigorousrnground sampling can result in an accurate assessment ofrncrop acreage. In this study to estimate the maize area, thernpoint frame sampling approach is adapted to the strip-likerncropping pattern on the North China Plain. Remoternsensing information is used to perform a cost-efficientrnstratification from which no-agricultural areas arernexcluded from ground survey. This information is alsornincluded in a later stage as an auxiliary estimator inrnregression analysis. The results showed that thernintegration of remote sensing information as an auxiliaryrnestimator can improve the confidence of estimation byrnreducing the variance of the estimates.