Published: Jul 23, 2018
Μ. Φουμέλης
Εμμ. Βασιλάκης

Three methods are descibed between the most frequently used for the estimation of hill slope from digital elevation models (DEM), the 'd8' method (Travis et al. 1975), Horn's method (1981) and Zevenbergen and Thorne method (1987), are described. Also a new approach was examined introduced by Tarboton (1997) called 'd-infinite' method. In order to investigate the spatial distribution of deviations between the examined methods, a statistical analysis was performed in a GIS environment. The magnitude of the differences between the methods was determined by calculating the RMSEr (Root Mean Square Error), while the degree of their equivalence was expressed by the linear correlation factor (r). Most deviations were located in areas of high relief, whereas the most interesting fact was that each method overestimates or underestimates the slope in very specific morphological structures, e.g. along watersheds, streams and generally in some types of morphological discontinuities. Finally, the DEM spatial resolution effect was explored on the estimated slope values using the selected methods. Regardless the method used, a general tendency of underestimating slope values by decreasing the DEM resolution was observed. The degree of divergences between these was also highly depended on the change of spatial resolution. Thus, the importance of defining a suitable resolution for each application should be addressed.

Article Details
  • Section
  • Remote Sensing and GIS
Download data is not yet available.
Fleming, M.D., Hoffer, R.M., 1979. Machine processing of landsat MSS data and DMA topographic data for forest cover type mapping, LARS Technical Report 062879. Laboratory for Applications of Remote Sensing, Purdue University, West Lafayette, Indiana.
Horn, B.K.P., 1981. Hill shading and reflectance map, Proceedings of the IEEE, 69(1), 14-47.
Jones, K.H., 1998. A comparison of algorithms used to compute hill slope as a property of the DEM, Computers & Geosciences, 24(4), 315-323.
Ripley, B.D., 1981. Spatial statistics. New York, John Wiley, 252p.
Sharpnack, D.A., Akin, G., 1969. An algorithm for computing slope and aspect from elevations, Photogrammetric Engineering, 35(3), 247-248.
Skidmore, A.K., 1989. A comparison of techniques for calculating gradient and aspect from a gridded digital elevation model, International Journal of Geographical Information Systems, 3(4), 323-334.
Strahler, A.N., 1952. Hypsometric (area-altitude) analysis of erosional topography, Geological Society of America Bulletin, 63, 1117-1142
Strahler, A.N., 1958. Dimensional analysis applied to fluvially eroded landforms, Geological Society of America Bulletin, 69, 279-300.
Tarboton, D.G., 1997. A new method for the determination of flow directions and upslope areas in grid digital elevation models, Water Resources Research, 33(2), 309-319.
Travis, M.R., Eisner, GH., Iverson, W.D., Johnson, CG., 1975. VIEWIT computation of seen areas, slope and aspect for land-use planning, U.S. Dept. of Agriculture Forest Service Gen. Techn. Rep. PSW 11/1975, Pacific Southwest Forest and Range Experimental Station, Berkley, California, 70pp.
Zevenbergen, L.W., Thome, C, 1987. Quantitative analysis of land surface topography, Earth Surface Processes and Landforms, 12, 47-56.
Zhang, X., Drake, N.A., Wainwright, J., Mulligan, M., 1999. Comparison of slope estimates from low resolution DEMs: Scaling issues and fractal method for their solution, Earth Surface Processes and Landforms, 24, 763-779.
Most read articles by the same author(s)