Figure 2 - uploaded by Alfred de Jager
Content may be subject to copyright.
Source publication
Mapping and characterisation of catchments and river courses for the
European continent is of relevant interest to support the environmental
monitoring activities of the European Environmental Agency (EEA) and for
the implementation of the Water Framework Directive (WFD). At
continental or global scale the river networks and associated catchments
a...
Similar publications
Water transparency is one of the ecological indicators for describing water quality and the underwater light field which determines its productivity. In the European Water Framework Directive (WFD) as well as in the European Marine Strategy Framework Directive (MSFD) water transparency is used for ecological status classification of inland, coastal...
The aim of this paper was to study and assess the quality of Bulgarian Black Sea coastal water using the biological quality element phytoplankton communities, according to the requirements of the Water Framework Directive (WFD EU, 2000) and the developed reference values. A total of 134 species of
microalgae were identified among which dominated th...
Citations
... In addition, coarse and medium resolution DEMs cannot resolve topographic features such as hollows, low-order channels, and hillslope characteristics [Zhang and Montgomery, 1994; Quinn et al., 1995]. Motivated by the need to generate a pan-European river network database from a coarse (cell size of 250m) grid digital elevation model [Vogt et al., 2002; Colombo et al., 2003], we introduce in this study three new algorithms for better determining local flow directions in the presence of spurious pits and large flat areas. These algorithms are based on concepts of mathematical morphology [Serra, 1982; Heijmans, 1994; Soille, 2003]. ...
1] An effective and widely used method for removing spurious pits in digital elevation models consists of filling them until they overflow. However, this method sometimes creates large flat regions which in turn pose a problem for the determination of accurate flow directions. In this study, we propose to suppress each pit by creating a descending path from it to the nearest point having a lower elevation value. This is achieved by carving, i.e., lowering, the terrain elevations along the detected path. Carving paths are identified through a flooding simulation starting from the river outlets. The proposed approach allows for adaptive drainage enforcement whereby river networks coming from other data sources are imposed to the digital elevation model only in places where the automatic river network extraction deviates substantially from the known networks. An improvement to methods for routing flow over flat regions is also introduced. Detailed results are presented over test areas of the Danube basin.
Irrelevant minima of an image are usually suppressed by a minima imposition technique based on a morphological reconstruction by erosion. In this paper, we present an alternative approach whereby each irrelevant minimum is discarded by creating a descending path linking it to the nearest point having a lower elevation value. This is achieved by carving the image intensity values along the detected path. An enhanced algorithm for the lower complete transformation enabling the definition of flow directions on flat zones is also described.
