PC-BASED 2-DIMENSIONAL DISCRETE FOURIER-TRANSFORM PROGRAMS FOR TERRAIN ANALYSIS

A two-dimensional Fast Fourier Transform (2D-FFT) program written in C language was developed for the personal computer with the specific pu rpose of extracting periodicities from digital elevation model (DEM) d ata. The program generates the individual frequency pairs, the coeffic ients representing the amplitudes of the cosine and sine waves, the an gle the wavefront makes in the terrain, the wavelength, the power of t he wave, the percent contribution the wave makes to the overall landsc ape, and finally the overall percentage of variance accounted for by t he model. The landscape can be reconstructed based on the number of si gnificant waveforms extracted. Generalizations on the spatial trends o f the terrain therefore can be made. The Fourier analysis provides ins ight to the nature and complexity of the terrain. An application of th e program to the karst landscape of Manati, Puerto Rico is illustrated . Copyright (C) 1996 Elsevier Science Ltd.