scholarly journals Assessment of vertical accuracy of open source 30m resolution space-borne digital elevation models

2021 ◽  
Vol 12 (1) ◽  
pp. 939-960
Author(s):  
Rocky Talchabhadel ◽  
Hajime Nakagawa ◽  
Kenji Kawaike ◽  
Kazuki Yamanoi ◽  
Bhesh Raj Thapa
Keyword(s):  
Open Source ◽  
Digital Elevation Models ◽  
Digital Elevation ◽  
Vertical Accuracy

scholarly journals Assessment of open source digital elevation models (SRTM-30, ASTER, ALOS) for erosion processes modeling

2019 ◽  
Vol 28 (1) ◽  
pp. 95-105 ◽  
Author(s):  
I. P. Kovalchuk ◽  
K. A. Lukianchuk ◽  
V. A. Bogdanets
Keyword(s):  
Open Source ◽  
Correlation Coefficient ◽  
Root Mean Square ◽  
Digital Elevation Models ◽  
Mean Square ◽  
Erosion Processes ◽  
Aster Gdem ◽  
Digital Elevation ◽  
Vertical Accuracy ◽  
Mean Square Errors

The relief has a major impact on the landscape`s hydrological, geomorphological and biological processes. Many geographic information systems used elevation data as the primary data for analysis, modeling, etc. A digital elevation model (DEM) is a modern representation of the continuous variations of relief over space in digital form. Digital Elevation Models (DEMs) are important source for prediction of soil erosion parameters. The potential of global open source DEMs (SRTM, ASTER, ALOS) and their suitability for using in modeling of erosion processes are assessed in this study. Shumsky district of Ternopil region, which is located in the Western part of Ukraine, is the area of our study. The soils of Shumsky district are adverselyaffected by erosion processes. The analysis was performed on the basis of the characteristics of the hydrological network and relief. The reference DEM was generated from the hypsographic data(contours) on the 1:50000 topographical map series compiled by production units of the Main Department of Geodesy and Cartography under the Council of Ministers. The differences between the reference DEM and open source DEMs (SRTM, ASTER and ALOS) are examined. Methods of visual detection of DEM defects, profiling, correlation, and statistics were used in the comparative analysis. This research included the analysis oferrors that occurred during the generation of DEM. The vertical accuracy of these DEMs, root mean square error (RMSE), absolute and relative errors, maximum deviation, and correlation coefficient have been calculated. Vertical accuracy of DEMs has been assessed using actual heights of the sample points. The analysis shows that SRTM and ALOS DEMs are more reliable and accurate than ASTER GDEM. The results indicate that vertical accuracy of DEMs is 7,02m, 7,12 m, 7,60 mand 8,71 m for ALOS, SRTM 30, SRTM 90 and ASTER DEMs respectively. ASTER GDEM had the highest absolute, relative and root mean square errors, the highest maximum positive and negative deviation, a large difference with reference heights, and the lowest correlation coefficient. Therefore, ASTER GDEM is the least acceptable for studying the intensity and development of erosion processes. The use of global open source DEMs, compared with the vectorization of topographic maps,greatly simplifies and accelerates the modeling of erosion processes and the assessment of the erosion risk in the administrative district.

scholarly journals Introducing QuickChi, a web application for near-global, exploratory, longitudinal river profile analysis

2021 ◽  
Author(s):  
Gregory Ruetenik
Keyword(s):  
Steady State ◽  
Open Source ◽  
Web Application ◽  
Profile Analysis ◽  
Digital Elevation Models ◽  
Global Scale ◽  
Exploratory Analysis ◽  
Tectonic Geomorphology ◽  
The Past ◽  
Digital Elevation

Stream profile analysis has been used extensively in the field of tectonic geomorphology. In the past, exploration of stream profiles, including χ-elevation profiles, has required downloading and processing Digital Elevation Models for specific areas, which limits the scope of exploratory analysis. Presented here is a web application designed to analyze stream profiles at 90m resolution at a near-global scale. Based on the Hydrosheds (Wickel et al., 2007) 90m drainage direction, as well as computed d8 drainage direction and void-filled DEMs, the app allows users to quickly query downstream from selected points anywhere within ±60 degrees latitude, in order to interactively analyze corresponding stream profiles in both distance and χ space, where χ is a metric that is proportional to the presumed steady-state shape of the stream profile (Perron and Royden, 2013). QuickChi is open source, and although currently it is designed as an exploratory tool, more functions can be easily added via community contributions and/or from existing toolsets.

scholarly journals Comparison of Vertical Accuracy of Open-Source Global Digital Elevation Models: A Case Study of Adama City, Ethiopia

2021 ◽  
Vol 12 (4) ◽  
pp. 1731-1744
Author(s):  
Hailu Zewde Abili
Keyword(s):  
Open Source ◽  
Thermal Emission ◽  
Accuracy Assessment ◽  
Shuttle Radar Topography Mission ◽  
Surface Model ◽  
Aster Gdem ◽  
Digital Elevation ◽  
Wide Range ◽  
Vertical Accuracy ◽  
Elevation Model

DEM can be generated from a wide range of sources including land surveys, Photogrammetry, and Remote sensing satellites. SRTM 30m DEM by The Shuttle Radar Topography Mission (SRTM), the Global Digital Elevation Model by Advanced Spaceborne Thermal Emission and Reflectance Radiometer (ASTER GDEM) and a global surface model called ALOS Worldview 3D 30 meter (AW3D30) by Advanced Land Observing Satellite (ALOS) are satellite-based global DEMs open-source DEM datasets. This study aims to assess the vertical accuracy of ASTER GDEM2, SRTM 30m, and ALOS (AW3D30) global DEMs over Ethiopia in the study area-Adama by using DGPS points and available accurate reference DEM data. The method used to evaluate the vertical accuracy of those DEMs ranges from simple visual comparison to relative and absolute comparisons providing quantitative assessment (Statistical) that used the elevation differences between DEM datasets and reference datasets. The result of this assessment showed better accuracy of SRTM 30m DEM (having RMSE of ± 4.63 m) and closely followed by ALOS (AW3D30) DEM which scored RMSE of ± 5.25 m respectively. ASTER GDEM 2 showed the least accuracy by scoring RMSE of ± 11.18 m in the study area. The second accuracy assessment was done by the analysis of derived products such as slope and drainage networks. This also resulted in a better quality of DEM derived products for SRTM than ALOS DEM and ASTER GDEM.

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