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| Titel |
Hydrography-driven coarsening of grid digital elevation models |
| VerfasserIn |
Giovanni Moretti, Stefano Orlandini |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250148230
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| Publikation (Nr.) |
 EGU/EGU2017-12467.pdf |
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| Zusammenfassung |
| Grid coarsening is commonly applied to high-resolution digital elevation models to obtain suitable meshes for distributed catchment models, especially when computational constrains inherent to large-scale and/or long-term simulations need to be satisfied. The nearest neighbor coarsening strategy is the standard method for this task. However, depitting after the nearest neighbor coarsening can yield significant alterations of land surface topography and extracted channel network. It is, therefore, relevant to seek for coarsening strategies that can better distill the information content of high-resolution digital elevation models to ultimately allow coarsened digital elevation models to yield accurate channel networks. A new grid coarsening strategy, denoted as hydrography-driven coarsening, is developed in the present study. In the hydrography-driven coarsening, (1) the high-resolution digital elevation model is depitted, (2) the obtained topographic data are used to extract a reference grid network, and (3) the Horton stream orders are assigned to each link of the extracted grid network. The elevation of the point lying along the highest-order stream within a coarse grid cell and displaying the minimum distance to the coarse grid cell center is assigned to that coarse grid cell. The capabilities of the hydrography-driven coarsening with respect to the standard nearest neighbor coarsening are evaluated over a synthetic valley and two real drainage basins located in the Italian Alps and in the Italian Apennines. The hydrography-driven coarsening method developed yields more accurate depitted digital elevation models than nearest neighbors coarsening. In addition, channels extracted after the proposed coarsening method are closer to observed channels than those extracted after standard coarsening. |
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