Spatial resolution of a digital elevation model defined by the wavelet function

Abstract

The objective of this work was to define the most appropriate spatial resolution to represent the variability of elevation, slope, profile curvature and topographic wetness index of a terrain by evaluations with the wavelet transform. Data used in the study have their origin in three 27‑km transects, positioned in areas of the Planalto, Rebordo do Planalto and Depressão Central in the central region of Rio Grande do Sul state, Brazil. The variables – elevation, slope, profile curvature and topographic wetness index – were derived from a Topodata digital elevation model with 30 m resolution. The assessment of the resolution with the highest variability was evaluated through the application of the Morlet mother wavelet. The results were analyzed from the wavelet coefficients plotted in isograms and scalograms, and indicate that remote sensors with spatial resolution between 32 and 40 m should be used in researches considering terrain attributes as slope, profile curvature and topographic wetness index, or even environmental phenomena related to them. However, it was not possible to establish a conclusive value for a more appropriate spatial resolution to the attribute elevation