High Speed DEM Construction Based on Local Least Squares Collocation

We have developed a local least squares collocation(LSC) method to decrease the computational cost of the classical LSC.Local LSC employs the divide-and-conquer method to determine the neighbor sampling points of the estimated one.The covariance matrix of residuals after trend removal is obtained with semivariance in geostatistics.The sampling points with the distance from the estimated one smaller than the range is used for local LSC computation.Numerical tests indicate that under the same simulation accuracy,local LSC is much faster than the classical one.The real-world example of simulating the DEM of Dongzhi tableland shows that LSC is more accurate than IDW and ordinary kriging.