scholarly journals Generating and analyzing Terrain characteristics from Shuttle Radar Topographic Mission (SRTM), DEM

2021 ◽  
Vol 10 (3) ◽  
pp. 198-206
Author(s):  
Ugbelase Vincent Nwacholundu ◽  
Igbokwe Joel Izuchukwu ◽  
Emengini Josephine Ebele ◽  
Ejikeme Joseph Onyedika ◽  
Igbokwe Esomchukwu Chinagorom
Keyword(s):  
Flow Direction ◽  
Digital Elevation Models ◽  
Random Noise ◽  
Analysis Tool ◽  
Terrain Analysis ◽  
Srtm Dem ◽  
Hydrologic Modelling ◽  
Shuttle Radar Topographic Mission ◽  
Digital Terrain ◽  
Digital Elevation

Terrain analysis is the quantitative analysis of topographic surfaces. The purpose of a digital terrain system is to provide the digital representation of terrain so that environmental problem like soil erosion may be approached accurately and efficiently through automated means. Traditionally this was (and still is!) being done manually by using topographic/contour maps. With the availability of Digital Elevation Models (DEM) and GIS tools, watershed properties can be extracted by using automated procedures. Remote Sensing and Digital elevation models (DEMs) are known to be very useful data sources for the automated delineation of flow paths, sub watersheds and flow networks for hydrologic modelling and watershed characterization. The digital terrain model was extracted from a 90m resolution Shuttle Radar Topographic Mission (SRTM) of the study area. The SRTM data was corrected by removing voids, striping, tree offsets and random noise. The SRTM DEM data was projected from geographic coordinate WGS 84 to UTM zone 32 of the study area. The 3-D analysis tool of the ArcGIS 10.1 was used for this process. The DEM was processed to obtain the Slope, Contour, Flow direction, Flow accumulation, Flow length, Stream power Index of the study area. The study proved that SRTM elevation dataset has the ability to obviate the lack of terrain data for hydrologic modelling using ArcGIS where appropriate data for terrain modelling and simulation of hydrological processes is unavailable.

Assessing the Impact of Uncertainties of Digital Elevation Models on Hydro-Geomorphological Analysis Using Gaussian White Noise

2020 ◽  
Author(s):  
Lukas Graf ◽  
Mariano Moreno-de-las-Heras ◽  
Joan Estrany
Keyword(s):  
White Noise ◽  
Imperfect Information ◽  
Digital Elevation Models ◽  
Gaussian White Noise ◽  
Terrain Analysis ◽  
Stream Network ◽  
Digital Terrain ◽  
Digital Elevation ◽  
The Impact ◽  
Geomorphological Analysis

<p><span>Digital elevation models (DEM) are mathematical representations of the Earth's bare surface in computer-readable format. The underlying measurements are often obtained by remote sensing and photogrammetry methods and processed into continuous raster data. Each of these data sources, however, provides imperfect information, and further processing steps often increase the degree of imperfection. Consequently, the process of DEM generation cumulates in uncertainty, which affects subsequent hydro- and geomorphological analyses and modelling (e.g., stream network delineation, flowpath distribution, erosion modelling).</span></p> <p><span>In many DEM-based studies, however, the aspect of uncertainty related to the DEM data source has been neglected. Therefore, we propose a new approach for quantifying the effects of DEM uncertainty on hydro-geomorphological modelling based on Gaussian white noise, a concept widely used in signal processing to map noise in signals and extract the actual message context. The basic idea is to add noise to the original DEM values by means of a Gaussian distribution whose parameters are determined from the mean value of the elevation values in a moving window and the device-specific properties (precision and accuracy).</span></p> <p><span>We postulate that such an approach can be used to determine uncertainties and their effect on subsequent analysis steps of hydro-geomorphological modelling. It is conceivable to create DEM ensembles depending on known parameters such as the accuracy and precision of the measuring instrument, as is used operationally in weather forecasting. Using such ensembles, probability ranges for terrain and catchment hydro-geomorphological properties can be determined and uncertainty ranges can be specified. Thus, the currently mostly deterministic approach of digital terrain modelling will be replaced by a more probabilistic understanding. Overall, our approach will help decision-makers and scientists to better assess the results of digital terrain analysis. Furthermore, it will also facilitate determining whether a result of DEM-based hydro-geomorphological analysis is sufficiently certain to answer specific research questions.</span></p>

scholarly journals Modelagem automática e cálculo da precipitação média da Bacia Hidrográfica do Rio Mundaú

2020 ◽  
Vol 9 (10) ◽  
pp. e4919108867
Author(s):  
Anderson Santos da Silva ◽  
Mário Melquíades Silva dos Anjos ◽  
Anthony Wellington Almeida Gomes ◽  
Alan Cézar Bezerra ◽  
Miguel Julio Machado Guimarães
Keyword(s):  
Digital Elevation Models ◽  
Terrain Analysis ◽  
Shuttle Radar Topographic Mission ◽  
Digital Elevation

As bacias hidrográficas desempenham um papel fundamental no desenvolvimento territorial desde que a exploração dos recursos naturais seja equilibrada tanto pela população quanto na gestão dos órgãos competentes. Assim, objetivou-se nessa pesquisa a delimitação automática e cálculo da precipitação média da Bacia Hidrográfica do Rio Mundaú (BHRM). A imagem foi processada no software livre QGIS 2.18.7 utilizando o conjunto de ferramentas embarcado no TauDEM (Terrain Analysis Using Digital Elevation Models) que dimensiona toda malha hidrológica através do uso de Modelo digital de Elevação (MDE) provenientes de dados altimétricos de imagem SRTM (Shuttle Radar Topographic Mission). Foi realizado todo tratamento na modelagem da rede de drenagem observando as remoções de depressões, declividades, canal principal, direções dos fluxos simples e múltiplos. Em seguida foi realizado o cálculo de precipitação média pelo método de Thiessen com subsídio de dados pluviométricos coletados em estações meteorológicas presentes no perímetro da bacia. Para complementação do trabalho, foram feitas umas caracterizações do relevo com uso do MDE obtido e assim corroborar com a interpretação dos resultados encontrados. Ficaram constatadas diferenças significativas entre os índices pluviométricos da BHRM entre o período de 2013 até 2019, pois no início da observação, o estado de Pernambuco e Alagoas vinha passando por um período de estiagem significativo justificando assim o reduzido volume pluviométrico. Em relação ao cômputo da área, houve uma diferença de mais de 400 km² na área da BHRM quando correlacionado com as informações dos órgãos oficiais, representando uma redução de aproximadamente 10%.

scholarly journals DETERMINING THE SUITABILITY OF DIFFERENT DIGITAL ELEVATION MODELS AND SATELLITE IMAGES FOR FANCY MAPS. AN EXAMPLE OF CYPRUS

2016 ◽  
Vol XLI-B4 ◽  
pp. 591-597
Author(s):  
J. Drachal ◽  
A. K. Kawel
Keyword(s):  
Small Area ◽  
Satellite Images ◽  
Digital Elevation Models ◽  
Test Area ◽  
Landsat 8 ◽  
Digital Terrain Models ◽  
Digital Terrain ◽  
Terrain Models ◽  
Digital Elevation ◽  
Shaded Relief

The article describes the possibility of developing an overall map of the selected area on the basis of publicly available data. Such a map would take the form designed by the author with the colors that meets his expectations and a content, which he considers to be appropriate. Among the data available it was considered the use of satellite images of the terrain in real colors and, in the form of shaded relief, digital terrain models with different resolutions of the terrain mesh. Specifically the considered data were: MODIS, Landsat 8, GTOPO-30, SRTM-30, SRTM-1, SRTM-3, ASTER. For the test area the island of Cyprus was chosen because of the importance in tourism, a relatively small area and a clearly defined boundary. In the paper there are shown and discussed various options of the Cyprus terrain image obtained synthetically from variants of Modis, Landsat and digital elevation models of different resolutions.

scholarly journals A NEW METHOD TO DEFINE FLOW DIRECTION USING GRID DIGITAL ELEVATION MODELS

2003 ◽  
Vol 47 ◽  
pp. 241-246
Author(s):  
Roshan SHRESTHA ◽  
Yasuto TACHIKAWA ◽  
Kaoru TAKARA
Keyword(s):  
Flow Direction ◽  
Digital Elevation Models ◽  
New Method ◽  
Digital Elevation

scholarly journals Application of the global SRTM and AW3D30 digital elevation models to mapping folds at cave sites

2021 ◽  
Vol 50 (1) ◽  
pp. 75-89
Author(s):  
Mark Abolins ◽  
Albert Ogden
Keyword(s):  
Cell Size ◽  
Forest Canopy ◽  
Digital Elevation Models ◽  
Digital Terrain Model ◽  
Surface Model ◽  
M Cell ◽  
Terrain Model ◽  
Digital Terrain ◽  
Digital Elevation ◽  
The Mean

A novel method to map and quantitatively describe very gentle folds (limb dip <5°) at cratonic cave sites was evaluated at Snail Shell and Nanna caves, central Tennessee, USA. Elevations from the global SRTM digital terrain model (DTM) were assigned to points on late Ordovician geologic contacts, and the elevations of the points were used to interpolate 28 m cell size natural neighbor digital elevation models (DEM’s) of the contacts. The global Forest Canopy Height Dataset was subtracted from the global 28 m cell size AW3D30 digital surface model (DSM) to create a DTM, and that DTM was applied in the same way. Comparison of mean and modal strikes of the interpolated surfaces with mean and modal cave passage trend shows that many passages are sub-parallel to the trend of an anticline. WithiSn 500 m of the caves, the SRTM- and AW3D30-based interpolated surfaces have mean strikes within 8° of the mean strike of an interpolated reference surface created with a high resolution (~0.76 m cell size and 10 cm RMSE) Tennessee, USA LiDAR DTM. This evaluation shows that the SRTM- and AW3D30-based method has the potential to reveal a relationship between the trend of a fold, on one hand, and cave passages, on the other, at sites where a geologic contact varies in elevation by >35 m within an area of <12.4 km2 and the mean dip of bedding is >0.9°.

scholarly journals Short Communication: TopoToolbox 2 – MATLAB-based software for topographic analysis and modeling in Earth surface sciences

2014 ◽  
Vol 2 (1) ◽  
pp. 1-7 ◽  
Author(s):  
W. Schwanghart ◽  
D. Scherler
Keyword(s):  
User Interfaces ◽  
Object Oriented Programming ◽  
Visual Exploration ◽  
Terrain Analysis ◽  
Topographic Analysis ◽  
Digital Terrain ◽  
Memory Overhead ◽  
Digital Elevation ◽  
Flow Directions ◽  
Derived Data

Abstract. TopoToolbox is a MATLAB program for the analysis of digital elevation models (DEMs). With the release of version 2, the software adopts an object-oriented programming (OOP) approach to work with gridded DEMs and derived data such as flow directions and stream networks. The introduction of a novel technique to store flow directions as topologically ordered vectors of indices enables calculation of flow-related attributes such as flow accumulation ∼20 times faster than conventional algorithms while at the same time reducing memory overhead to 33% of that required by the previous version. Graphical user interfaces (GUIs) enable visual exploration and interaction with DEMs and derivatives and provide access to tools targeted at fluvial and tectonic geomorphologists. With its new release, TopoToolbox has become a more memory-efficient and faster tool for basic and advanced digital terrain analysis that can be used as a framework for building hydrological and geomorphological models in MATLAB.

scholarly journals Analysing the Potential of OpenStreetMap Data to Improve the Accuracy of SRTM 30 DEM on Derived Basin Delineation, Slope, and Drainage Networks

Hydrology ◽  
2018 ◽  
Vol 5 (3) ◽  
pp. 34 ◽  
Author(s):  
Elisabete Monteiro ◽  
Cidália Fonte ◽  
João Lima
Keyword(s):  
Spatial Resolution ◽  
Digital Elevation Models ◽  
Original Data ◽  
Shuttle Radar Topography Mission ◽  
Vertical Position ◽  
Hydrologic Modelling ◽  
Ordnance Survey ◽  
Drainage Networks ◽  
Useful Components ◽  
Digital Elevation

Terrain slope and drainage networks are useful components to the basins morphometric characterization as well as to hydrologic modelling. One way to obtain the slope, drainage networks, and basins delineation is by their extraction from Digital Elevation Models (DEMs) and, therefore, their accuracy depends on the accuracy of the used DEM. Regional DEMs with high detail and accuracy are produced in many countries by National Mapping Agencies (NMA). However, the use of these products usually has associated costs. An alternative to those DEMs are the Global Digital Elevation Models (GDEMs) that can be accessed freely and cover almost the entire surface of the world. However, they are not as accurate as the regional DEMs obtained with other techniques. This study intends to assess if generating new, modified DEMs using altimetric data from the original GDEMs and the watercourses available for download in the collaborative project OpenStreetMap (OSM) improves the accuracy of the rebuilt DEMs, the slope derived from them, as well as the delineation of basins and the horizontal and vertical accuracy of the extracted drainage networks. The methodology is presented and applied to a study area located in the United Kingdom. The GDEMs used are of 30 m spatial resolution from the Shuttle Radar Topography Mission (SRTM 30). The accuracy of the original data and the data obtained with the proposed methodology is compared with a reference DEM, with a spatial resolution of 50 m, and the rivers network available at the Ordnance Survey website. The results mainly show an improvement of the horizontal accuracy of the drainage networks, but also a decrease of the systematic errors of the new DEMs, the derived slope, and the vertical position of the drainage networks, as well as the basin’s identification for a set of pour points.

scholarly journals Application of 30m Resolution SRTM DEM in Nepal

2018 ◽  
Vol 14 (1) ◽  
pp. 235-240 ◽  
Author(s):  
Raghunath Jha
Keyword(s):  
High Resolution ◽  
Digital Terrain Model ◽  
Topographic Map ◽  
Srtm Dem ◽  
Terrain Model ◽  
Digital Terrain ◽  
Digital Elevation ◽  
Raster Analysis ◽  
Elevation Model ◽  
Almost All

 Digital Terrain Model (DTM) or Digital Elevation Model (DEM) is an important data for Raster Analysis in modern GIS. Its use is extremely important for almost all fields of engineering, especially Water Resources Engineering. In Nepal, high-resolution DTM is not available, and often funds are limited to generate high-resolution DTM using modern day technology such as LiDAR or Aerial Photography. As a result most of the works are based on SRTM DEM which is available free of cost. Presently, 1arc second DTM is available in SRTM for Nepalese Territories. In this study, the applicability of 1arc second or 30m resolution SRTM is checked in comparison with the Department of Survey Digital Topographic Map. It is found that SRTM DEM performs better than DEM generated from Data available with Survey Department.Journal of the Institute of Engineering, 2018, 14(1): 235-240

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