Centre de documentation
scientifique

Comparison of automated watershed delineations: effects on land cover areas, percentages, and relationships to nutrient discharges / M.E. Baker in Photogrammetric Engineering & Remote Sensing, PERS, vol 72 n° 2 (February 2006)  

Public [article]  inPhotogrammetric Engineering & Remote Sensing, PERS > vol 72 n° 2 (February 2006) . - pp 159 - 168 Titre : Comparison of automated watershed delineations: effects on land cover areas, percentages, and relationships to nutrient discharges Type de document : Article/Communication Auteurs : M.E. Baker, Auteur ; D.E. Weller, Auteur ; T.E. Jordan, Auteur Année de publication : 2006 Article en page(s) : pp 159 - 168 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications photogrammétriques [Termes IGN] analyse comparative [Termes IGN] automatisation [Termes IGN] bassin hydrographique [Termes IGN] Chesapeake (baie de) [Termes IGN] détection de contours [Termes IGN] modèle numérique de surface [Termes IGN] nitrate [Termes IGN] occupation du sol [Termes IGN] parcelle agricole [Termes IGN] sédiment Résumé : (Auteur) We compared manual delineations with those derived from ten automated delineations of 420 watersheds in four physiographic provinces of the Chesapeake Basin. Automated methods included commercial DEM-based routines and different parameterizations of four enhanced methods: stream burning, normalized excavation, surface reconditioning, and normalized reconditioning. Un-enhanced methods resulted in individual watershed boundaries with some gross discrepancies in watershed size relative to manual delineations (error rate of 0.22 > 25 percent difference compared to manual) and significantly different watershed size distributions (Mann-Whitney U p = 0.012). Integrating mapped streams through enhanced methods substantially improved correspondence with manual watersheds (error rates of only 0.08-0.02 > 25 percent difference). Analysis of cropland area among methods showed a significant difference between manual estimates and un-enhanced estimates (p = 0.049) that was corrected using enhanced algorithms. Subsequent analysis of percent cropland revealed that measurements of land cover proportions were not always affected by delineation errors. However, differences were large enough to influence regressions with stream nitrate-N at the 90 percent confidence level within one physiographic province. Enhanced delineations produced statistical relationships between percent cropland and nitrate-N concentrations consistent with manual delineations. The results provide support for enhanced automated watershed delineation within the Chesapeake Basin and suggest that normalized excavation can be an effective augmentation of existing stream burning and reconditioning procedures. Numéro de notice : A2006-038 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.14358/PERS.72.2.159 En ligne : https://doi.org/10.14358/PERS.72.2.159 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=27765 [article]