The method is exemplified by a portion of the Great Rift Valley and central Kenyan highlands. A DEM of this territory the matrix 480 × 481 with a grid spacing of 30″ was extracted from the global DEM SRTM30_PLUS. We evaluated various sets of expansion coefficients up to 7000 to approximate and reconstruct DEMs with and without the Fejer summation. Digital models of horizontal and vertical curvatures were computed using the first and second partial derivatives of elevation derived from the reconstructed DEMs. To evaluate the approximation accuracy, digital models of residuals differences between the reconstructed DEMs and the initial one were calculated. The test results demonstrated that the method is characterized by a good performance i.e., a distinct monotonic convergence of the approximation and a high speed of data processing. The method can become an effective alternative to common techniques of DEM processing.
['Igor V. Florinsky', 'A. N. Pankratov']
A universal spectral analytical method for digital terrain modeling