LAN Tool: A GIS Tool for the Improvement of Digital Elevation Models Using Drainage Network Attributes (original) (raw)
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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. ᭧
Global Journal of Pure and Applied Sciences, 2022
This research used points extracted from high-resolution DEMs (1m) to investigate the impact of resolution, interpolation method and topography on the accuracy of drainage network extraction. The investigation was conducted by evaluating the accuracy of the estimations of streams length, streams number, drainage density, and the Longitudinal Root Mean Square Error (LRMSE) of the extracted drainage networks from different DEMs interpolated using Topo to raster, Natural Neighbor (NN), kriging and IDW interpolation methods at 5, 10, 15 and 20m resolutions over moderate, steep, and gentle slope terrain. Each evaluation conducted yielded a different result, but the accuracy of the streams length estimation for most of the DEMs at all the sites increases with an increase in streams order. The total lengths of all the streams of each of the extracted networks at gentle and steep slope sites are shorter than those of the corresponding reference networks though, 15 and 20m kriging and IDW DEMs created longer streams at the moderate slope site. IDW DEMs have proven reliable for streams length estimation while Topo to raster 5, 10, and 15m for streams number estimation. In general, N.N. extracted networks are the only networks that show consistency in the streams length and number estimations, drainage density estimation as well as in LRMSE and DEM RMSE computation at all the resolutions and for all the sites. Therefore, the accuracy of N.N. DEMs and their derivatives do not rapidly change with change in resolution, especially between 5 and 20m at all (steep, gentle and moderate) terrain types.
Digital terrain modelling: A review of hydrological, geomorphological, and biological applications
Hydrological Processes, 1991
The topography of a catchment has a major impact on the hydrological, geomorphological. and biological processes active in the landscape. The spatial distribution of topographic attributes can often be used as an indirect measure of the spatial variability of these processes and allows them to be mapped using relatively simple techniques. Many geographic information systems are being developed that store topographic information as the primary data for analysing water resource and biological problems. Furthermore, topography can be used to develop more physically realistic structures for hydrologic and water quality models that directly account for the impact of topography on the hydrology. Digital elevation models are the primary data used in the analysis of catchment topography. We describe elevation data sources, digital elevation model structures, and the analysis of digital elevation data for hydrological, geomorphological, and biological applications. Some hydrologic models that make use of digital representations of topography are also considered.
Evaluating preprocessing methods of digital elevation models for hydrological modelling
Hydrological Processes
With the introduction of high-resolution digital elevation models, it is possible to use digital terrain analysis to extract small streams. In order to map streams correctly, it is necessary to remove errors and artificial sinks in the digital elevation models. This step is known as preprocessing and will allow water to move across a digital landscape. However, new challenges are introduced with increasing resolution because the effect of anthropogenic artefacts such as road embankments and bridges increases with increased resolution. These are problematic during the preprocessing step because they are elevated above the surrounding landscape and act as artificial dams. The aims of this study were to evaluate the effect of different preprocessing methods such as breaching and filling on digital elevation models with different resolutions (2, 4, 8, and 16 m) and to evaluate which preprocessing methods most accurately route water across road impoundments at actual culvert locations. A unique dataset with over 30,000 field-mapped road culverts was used to assess the accuracy of stream networks derived from digital elevation models using different preprocessing methods. Our results showed that the accuracy of stream networks increases with increasing resolution. Breaching created the most accurate stream networks on all resolutions, whereas filling was the least accurate. Burning streams from the topographic map across roads from the topographic map increased the accuracy for all methods and resolutions. In addition, the impact in terms of change in area and absolute volume between original and preprocessed digital elevation models was smaller for breaching than for filling. With the appropriate methods, it is possible to extract accurate stream networks from high-resolution digital elevation models with extensive road networks, thus providing forest managers with stream networks that can be used when planning operations in wet areas or areas near streams to prevent rutting, sediment transport, and mercury export.
ISPRS International Journal of Geo-Information
This study describes a new method developed to determine the 3D positional displacements of the drainage networks extracted from Digital Elevation Models (DEMs). The proposed method establishes several stages for data preparation. The displacements are derived by means of linestring-based assessment methods, which can be applied in 2D and 3D. Also, we propose the use of several tools (maps, aggregation of results, new indices, etc.) in order to obtain a wider assessment of positional accuracy, or a time change analysis. This approach supposes a novelty in drainage network studies both in the application of line-based methods and its expansion to 3D data. The method has been tested using a sample of channels extracted from DEMs of two different dates of a zone of about 600 square kilometers using as reference linestrings those extracted from another more recent DEM which had higher spatial accuracy and higher spatial resolution. The results have demonstrated the viability of the method proposed because of the obtaining of 3D displacement vectors, which showed the general and particular behavior of the channels selected.
Numerical definition of drainage network and subcatchment areas from Digital Elevation Models
Computers & Geosciences, 1992
A set of ten algorithms to automate the determination of drainage network and subcatchment areas from Digital Elevation Models (DEMs) is presented. The algorithms perform such tasks as: DEM aggregation; depression identification and treatment; relief incrementation of fiat areas; flow vector determination; watershed boundary delineation; drainage network and subcatchment area definition and systematic indexing; tabulation of channel and subcatchment area properties; and evaluation of drainage network composition. A computer program (written in FORTRAN 77) that integrates these algorithms for a full DEM evaluation also is discussed. The primary purpose of the algorithms and computer program is to parameterize rapidly drainage network and subcatchment properties from widely available DEMs for subsequent use in hydrologic surface runoff models, watershed discretizations, or statistical and topological evaluation of drainage networks. Selected results of a DEM evaluation are presented for illustration purposes.
International Journal of Research Publication and Reviews, 2024
Flooding is a natural disaster that often occurs and has a significant impact on society and the environment. This can result in economic loss, infrastructure damage, disruption to daily life, and even loss of life. To mitigate the negative impacts of flooding, an in-depth understanding of the potential for flooding in an area is very important. One effective approach is to use spatial modeling to create flood vulnerability models, based on topographic data such as slope maps and contour maps. ALOS PALSAR DEM data, with a spatial resolution of 12.5 meters, offers important advantages in creating slope maps and contour maps for flood potential analysis. As a synthetic aperture radar technology, ALOS PALSAR collects topographic data with high accuracy and wide coverage, even in adverse weather conditions or areas with high cloud cover. Its ability to penetrate clouds makes ALOS PALSAR data more reliable and consistent than optical data, which may be limited by weather conditions. Slope maps show varying degrees of terrain steepness across the study area. Contour lines are successfully created, illustrating elevation changes in the landscape. GIS analysis highlights areas with high slope values and the potential to become flood-prone zones. DEM-derived maps serve as valuable tools for flood vulnerability modeling and risk assessment. Integration of DEM imagery with GIS techniques has proven effective in creating accurate and detailed slope and contour maps. These maps provide important information for identifying flood-prone areas and formulating effective disaster management strategies. This study underscores the importance of terrain analysis in flood vulnerability assessment and emphasizes the usefulness of DEM-derived data for spatial modeling.
Use of Digital Elevation Model to compute Storm Water Drainage Network
INTERNATIONAL JOURNAL OF ENGINEERING SCIENCES & RESEARCH TECHNOLOGY, 2014
Often planners and engineers are faced with various options and questions in storm drainage network design e.g. topography, flow pattern, direction and therefore size of drain or scenario after a road, airfield or building has been constructed. In most instances planning without drainage in mind has caused failure or extensive damage to property including the storm water drains which channel the water away. With the advent of GIS tools this problem can be averted. The Bhimrad area of surat city (Gujrat, India) had no storm drainage network for persistent flooding. This paper describes a method of assessing the effectiveness of storm drainage networks by a Digital Elevation Model (DEM). The DEM was generated from .dwg contour map and the data imported into ArcGIS, The 141.91hactor basin was then delineated into sub-catchments using ArcGIS Hydro extension tools. Also to derive impervious land cover, arial image of study area (Bhimrad) was accessed through ArcMap’s built-in base map function. The roads, buildings, canal, creek, water body existing land use were obtained by digitizing arial image. By overlaying the natural flow lines derived from the DEM with the reconstructed physical drains a comparison of the flow direction and the orientation of the drains was achieved. It is particularly useful for new areas where development is being contemplated. Keywords: Storm Drainage, Digital
The impact of resolution on the accuracy of hydrologic data derived from DEMs
Journal of Geographical …, 2001
Hydrologic data derived from digital elevation models (DEM) has been regarded as an effective method in the spatial analysis of geographical information systems (GIS). However, both DEM resolution and terrain complexity has impacts on the accuracy of hydrologic derivatives. In this study, a multi-resolution and multi-relief comparative approach was used as a major methodology to investigate the accuracy of hydrologic data derived from DEMs. The experiment reveals that DEM terrain representation error affects the accuracy of DEM hydrological derivatives (drainage networks and watershed etc.). Coarser DEM resolutions can usually cause worse results. However, uncertain result commonly exists in this calculation. The derivative errors can be found closely related with DEM vertical resolution and terrain roughness. DEM vertical resolution can be found closely related with the accuracy of DEM hydrological derivatives, especially in the smooth plain area. If the mean slope is less than 4 degrees, the derived hydrologic data are usually unreliable. This result may be helpful in estimating the accuracy of the hydrologic derivatives and determining the DEM resolution that is appropriate to the accuracy requirement of a particular user. By applying a threshold value to subset the cells of a higher accumulation flow, a stream network of a specific network density can be extracted. Some very important geomorphologic characteristics, e.g., shallow and deep gullies, can be separately extracted by means of adjusting the threshold value. However, such a flow accumulationbased processing method can not correctly derive those streams that pass through the working area because it is hard to accumulate enough flow direction values to express the stream channels at the stream's entrance area. Consequently, errors will definitely occur at the stream's entrance area. In addition, erroneous derivatives can also be found in deriving some particular rivers, e.g., perched (hanging up) rivers, anastomosing rivers and braided rivers. Therefore, more work should be done to develop and perfect the algorithms.