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An adaptive approach to selecting a flow-partition exponent for a multiple-flow-direction algorithm / C. Qin in International journal of geographical information science IJGIS, vol 21 n° 3-4 (march - april 2007)  

Public [article]  inInternational journal of geographical information science IJGIS > vol 21 n° 3-4 (march - april 2007) . - pp 443 - 458 Titre : An adaptive approach to selecting a flow-partition exponent for a multiple-flow-direction algorithm Type de document : Article/Communication Auteurs : C. Qin, Auteur ; A - Xing Zhu, Auteur ; Tao Pei, Auteur ; et al., Auteur Année de publication : 2007 Article en page(s) : pp 443 - 458 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications SIG [Termes IGN] bassin hydrographique [Termes IGN] Chine [Termes IGN] flux [Termes IGN] modèle numérique de surface [Termes IGN] partition de surface [Termes IGN] système d'information géographique Résumé : (Auteur) Most multiple-flow-direction algorithms (MFDs) use a flow-partition coefficient (exponent) to determine the fractions draining to all downslope neighbours. The commonly used MFD often employs a fixed exponent over an entire watershed. The fixed coefficient strategy cannot effectively model the impact of local terrain conditions on the dispersion of local flow. This paper addresses this problem based on the idea that dispersion of local flow varies over space due to the spatial variation of local terrain conditions. Thus, the flow-partition exponent of an MFD should also vary over space. We present an adaptive approach for determining the flow-partition exponent based on local topographic attribute which controls local flow partitioning. In our approach, the influence of local terrain on flow partition is modelled by a flow-partition function which is based on local maximum downslope gradient (we refer to this approach as MFD based on maximum downslope gradient, MFD-md for short). With this new approach, a steep terrain which induces a convergent flow condition can be modelled using a large value for the flow-partition exponent. Similarly, a gentle terrain can be modelled using a small value for the flow-partition exponent. MFD-md is quantitatively evaluated using four types of mathematical surfaces and their theoretical 'true' value of Specific Catchment Area (SCA). The Root Mean Square Error (RMSE) shows that the error of SCA computed by MFD-md is lower than that of SCA computed by the widely used SFD and MFD algorithms. Application of the new approach using a real DEM of a watershed in Northeast China shows that the flow accumulation computed by MFD-md is better adapted to terrain conditions based on visual judgement. Copyright Taylor & Francis Numéro de notice : A2007-120 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1080/13658810601073240 En ligne : https://doi.org/10.1080/13658810601073240 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28483 [article]

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