Best Unbiased Estimator for Trend——A Method of Getting Trend of Digital Elevation Model

Best unbiased estimator for trend，a method for getting trend of terrain elevation data，is given．It is an estimation method with high precision and good effectiveness．Trend datum in a point is estimated according to the digital elevation data in some information points around it． The estimation of trend is linear unbiased and with minimum variance of estimation．It has many advantages over the trend analysis method．