Carving and adaptive drainage enforcement of grid digital elevation models (original) (raw)
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Drainage networks from grid digital elevation models
Water resources research, 1991
Current algorithms that deduce the drainage network from a digital elevation model (DEM) represented by a regular array of surface elevations share a fault: Unless the terrain is rugged, the derived water channels tend to flow in parallel lines along preferred directions engendered by the ...
A flooding algorithm for extracting drainage networks from unprocessed digital elevation models
Computers & Geosciences, 2013
A new method for extracting the drainage network from a digital elevation model (DEM) is presented. It is based on the well-known D8 approach that simulates the overland flow but uses a more elaborate water transfer model that is inspired by the natural behaviour of water. The proposed solution has several advantages: it works on unprocessed DEMs avoiding the problems caused by pits and flats, can generate watercourses with a width greater than one cell and detects fluvial landforms like lakes, marshes or river islands that are not directly handled by most previous solutions.
Journal of Hydrology, 1995
provides an excellent review of a number of methods for the automated delineation of valley lines and drainage networks from grid digital elevation models (DEM). She identifies two fundamental problems in using the overland flow simulation approach to delinate fully-connected and directed networks of single-cell width, and suggests ways in which these might be addressed. The problems identified are: (1) positioning of the source nodes or upstream ends of the drainage network; (2) assignment of flow directions in flat and depressional areas of the DEM. These are significant problems and methodological improvements are needed to address them. However, the methodological improvements suggested by Tribe have shortcomings which create a new set of problems as serious as those which they are intended to correct. These shortcomings are discussed in the following.
An Efficient Assignment of Drainage Direction Over Flat Surfaces in Raster Digital Elevation Models
Computers and Geosciences, 2014
In processing raster digital elevation models (DEMs) it is often necessary to assign drainage directions over flats—that is, over regions with no local elevation gradient. This paper presents an approach to drainage direction assignment which is not restricted by a flat's shape, number of outlets, or surrounding topography. Flow is modeled by superimposing a gradient away from higher terrain with a gradient towards lower terrain resulting in a drainage field exhibiting flow convergence, an improvement over methods which produce regions of parallel flow. This approach builds on previous work by Garbrecht and Martz (1997), but presents several important improvements. The improved algorithm guarantees that flats are only resolved if they have outlets. The algorithm does not require iterative application; a single pass is sufficient to resolve all flats. The algorithm presents a clear strategy for identifying flats and their boundaries. The algorithm is not susceptible to loss of floating-point precision. Furthermore, the algorithm is efficient, operating in O(N) time whereas the older algorithm operates in O(N3/2) time. In testing, the improved algorithm ran 6.5 times faster than the old for a 100x100 cell flat and 69 times faster for a 700x700 cell flat. In tests on actual DEMs, the improved algorithm finished its processing 38–110 times sooner while running on a single processor than a parallel implementation of the old algorithm did while running on 16 processors. The improved algorithm is an optimal, accurate, easy-to-implement drop-in replacement for the original. Pseudocode is provided in the paper and working source code is provided in the Supplemental Materials.
The assignment of drainage direction over flat surfaces in raster digital elevation models
Journal of Hydrology, 1997
Drainage direction assignment over flat surfaces in raster Digital Elevation Models (DEM) has been a stubborn problem for DEM processing methods. A new approach that improves upon current methods of flat surface treatment is presented. The approach is based on the recognition that in natural landscapes drainage is generally away from higher and towards lower terrain. To produce such a drainage, DEM elevations of a flat surface are modified to impose two gradients: one away from higher terrain, and one towards lower terrain. Subsequent processing of the DEM produces a drainage pattern over the flat surface that is topographically consistent and exhibits flow convergence properties. The proposed approach is not restricted by the shape of the flat surface, the number of outlets on its edge, or the complexity of the surrounding topography. A comparison with the drainage pattern of an established method that displays the 'parallel flow' problem shows significant improvements in producing realistic drainage patterns. The proposed approach extends automated DEM processing to digital landscapes for which existing methods cannot provide adequate flow directions over flat surfaces to conduct a drainage analysis. The necessary algorithmic details for implementation of the approach are provided. © 1997 Elsevier Science B.Y.
Water Resources Research, 2003
Path-based methods for the determination of nondispersive drainage directions in grid-based digital elevation models are presented. These methods extend the descriptive capabilities of the classical D8 method by cumulating the deviations between selected and theoretical drainage directions along the drainage paths. It is shown that either angular or transversal deviations can be employed. Accordingly, two classes of methods designated D8-LAD (eight drainage directions, least angular deviation) and D8-LTD (eight drainage directions, least transversal deviation) are developed. Detailed tests on four synthetic drainage systems of known geometry and on the Liro catchment (central Italian Alps) indicate that the proposed methods provide significant improvement over the D8 method for the determination of drainage directions and drainage areas.
A comparison of drainage networks derived from digital elevation models at two scales
Journal of Hydrology, 1998
Automated generation of drainage networks has become increasingly popular with powerful analytical functions in geographic information systems (GIS) and with the increased availability of digital elevation models (DEMs). This paper compares drainage networks derived from DEMs at two scales, 1:250 000 (250K) and 1:24 000 (24K), using various drainage parameters common in hydrology and geomorphology. The comparison of parameters derived from the 250K DEMs with those from the 24K DEMs in 20 basins ranging from 150 to 1000 km 2 in West Virginia shows that the goodness-of-fit between parameter estimates based on the DEMs varies. Results clearly show that superior estimations are produced from the 24K DEMs. Better estimates can be obtained from the 250K DEMs for stream length and frequency parameters than for gradient parameters. However, the estimation of the mean gradient parameters based on the 250K DEMs seems to improve with increasing terrain complexity. Finally, basin size does not strongly affect the accuracy of parameter estimates based on the 250K DEMs. ᭧
Water, 2020
Flood simulation and hydrodynamic modeling of river flow require a dense sequence of river cross-sections. These cross-sections should be perpendicular to the flow path and are usually obtained through an in-field survey that is both a costly and time-consuming procedure. An alternative way to get these river cross-sections is to extract them from Digital Elevation Models (DEM). The accuracy achieved, though, depends on the quality and the resolution of the DEM available. Although there are specialized computer programs available for this process, the entire work must be mainly done manually. Some researchers have presented methods for the automatic extraction, but the cross-sections “produced” are restricted to be planar. This restriction does not ensure that they are perpendicular to the flow at all positions and does not allow them to be close to each other. In this paper, a new method is presented that, along with the algorithm developed, is fully parametric and allows non-plana...
Advances in the mapping of flow networks from digital elevation data
2001
Digital elevation models (DEMs) are a useful data source for the automatic delineation of flow paths, sub watersheds and flow networks for hydrologic modeling. Digital representation of the flow network is central to distributed hydrologic models because it encodes the model element linkages through which flow is routed to the outlet. The scale (drainage density) of the flow network, used controls the scale of hillslope and channel model elements. Although field mapping is acknowledged as the most accurate way to determine channel networks and drainage density, it is often impractical, especially for large watersheds, and DEM derived flow networks then provide a useful surrogate for channel or valley networks. There are a variety of approaches to delineating flow networks, using different algorithms such as single (drainage to a single neighboring cell) and multiple (partitioning of flow between multiple neighboring cells) flow direction methods for the computation of contributing area and local identification of upwards curvature. The scale of the delineated network is sometimes controlled by a support area threshold, which may impose an arbitrary and spatially constant drainage density. This paper examines methods for the delineation of flow networks using grid DEMs. We examine the question of objective estimation of drainage density and describe a method based on terrain curvature that can accommodate spatially variable drainage density. The methods presented have been incorporated as a component of the TMDL Toolkit software developed to support hydrologic and water quality modeling and available from