Lucian Drăguţ1,2, Clemens Eisank1, Thomas Strasser1, Thomas Blaschke1
1 Department of Geography and Geology, University of Salzburg, Hellbrunnerstraße 34, Salzburg 5020, Austria
2 Department of Geography, West University of Timişoara, V. Pârvan Blv. 4, Timişoara 300223, Romania
Telephone: (+43) 662 8044 5293
Fax: (+43) 662 8044 5260
Although debated, it seems to be unsettled if scales in digital representations of the land surface are explicitly detectable, or if scale is a ‘window of perception’ (Marceau 1999). In geomorphometry, scale is predominantly considered as a function of DEM resolution (Hengl and Evans 2009; MacMillan and Shary 2009). Increasing availability of high resolution DEMs is leading to a shift of paradigm regarding scale issues in geomorphometry. While in the past researchers were looking for finer resolution DEMs as a premise for improving analysis, now when they are available there is growing evidence that higher levels of detail represent just noise for some applications. This raises interest for considering scale issues in geomorphometry.
The scale dependency of land-surface parameters and objects derived from DEMs has been demonstrated in a number of studies (Wood 1996, 2009; Florinsky and Kuryakova 2000; Evans 2003; Fisher et al. 2004; Schmidt and Andrew 2005; Hengl 2006; Arrell et al. 2007; Drăguţ et al. 2009) and methods to account for scale through DEM generalization have been proposed. However, a comprehensive assessment of scaling methods- particularly from the perspective of their suitability of enabling scale detection- is still missing. This motivates our work. Several methods to generate scale levels were selected to comparatively evaluate their performances under controlled conditions.