SCALE DEPENDENCE IN TERRAIN ANALYSIS

Topographic attributes computed from digital elevation models are depe ndent on the resolution of the elevation data from which they are comp uted. A regular rectangular grid is not an ideal representation of top ographic surfaces for the study of scale effects. Spectral and wavelet techniques are obvious alternatives but have several deficiencies, pa rticularly in their use of oscillatory basis functions. The positive w avelet representation has very attractive properties of localisation a nd feature representation. Preliminary application to one-dimensional topographic data (profiles) yields useful results, including the ident ification of changes in topographic structure with scale. Extension to two-dimensional analysis will allow quantification of characteristic shapes, scales and orientations in the landscape.