scholarly journals COMPARATIVE ANALYSIS OF GLOBAL DIGITAL ELEVATION MODELS AND ULTRA-PROMINENT MOUNTAIN PEAKS

2016 ◽  
Vol III-4 ◽  
pp. 17-23 ◽  
Author(s):  
Carlos H. Grohmann
Keyword(s):  
Comparative Analysis ◽  
Digital Elevation Models ◽  
Full Range ◽  
Regional Scale ◽  
Comparative Assessment ◽  
Moving Window ◽  
Scale Analysis ◽  
Smoothing Effect ◽  
New Techniques ◽  
Digital Elevation

Global Digital Elevation Models (GDEMs) are datasets of vital importance for regional-scale analysis in areas such as geomorphology, [paleo]climatology, oceanography and biodiversity. In this work I present a comparative assessment of the datasets ETOPO1 (1’ resolution), GTOPO30, GLOBE, SRTM30 PLUS, GMTED2010 and ACE2 (30”) against the altitude of the world’s ultra prominent peaks. GDEMs’ elevations show an expected tendency of underestimating the peak’s altitude, but differences reach 3,500 m. None of the GDEMs captures the full range of elevation on Earth and they do not represent well the altitude of the most prominent peaks. Some of these problems could be addressed with the release of NASADEM, but the smoothing effect caused by moving-window resampling can only be tackled by using new techniques, such as scale-adaptative kernels and curvature-based terrain generalisation.

scholarly journals COMPARATIVE ANALYSIS OF GLOBAL DIGITAL ELEVATION MODELS AND ULTRA-PROMINENT MOUNTAIN PEAKS

2016 ◽  
Vol III-4 ◽  
pp. 17-23
Author(s):  
Carlos H. Grohmann
Keyword(s):  
Comparative Analysis ◽  
Digital Elevation Models ◽  
Full Range ◽  
Regional Scale ◽  
Comparative Assessment ◽  
Moving Window ◽  
Scale Analysis ◽  
Smoothing Effect ◽  
New Techniques ◽  
Digital Elevation

Global Digital Elevation Models (GDEMs) are datasets of vital importance for regional-scale analysis in areas such as geomorphology, [paleo]climatology, oceanography and biodiversity. In this work I present a comparative assessment of the datasets ETOPO1 (1’ resolution), GTOPO30, GLOBE, SRTM30 PLUS, GMTED2010 and ACE2 (30”) against the altitude of the world’s ultra prominent peaks. GDEMs’ elevations show an expected tendency of underestimating the peak’s altitude, but differences reach 3,500 m. None of the GDEMs captures the full range of elevation on Earth and they do not represent well the altitude of the most prominent peaks. Some of these problems could be addressed with the release of NASADEM, but the smoothing effect caused by moving-window resampling can only be tackled by using new techniques, such as scale-adaptative kernels and curvature-based terrain generalisation.

scholarly journals Setting the Flow Accumulation Threshold Based on Environmental and Morphologic Features to Extract River Networks from Digital Elevation Models

2021 ◽  
Vol 10 (3) ◽  
pp. 186
Author(s):  
HuiHui Zhang ◽  
Hugo A. Loáiciga ◽  
LuWei Feng ◽  
Jing He ◽  
QingYun Du
Keyword(s):  
Spatial Scales ◽  
Digital Elevation Models ◽  
Regional Scale ◽  
Drainage Density ◽  
River Network ◽  
Landscape Patterns ◽  
Estimation Methods ◽  
River Networks ◽  
Flow Accumulation ◽  
Digital Elevation

Determining the flow accumulation threshold (FAT) is a key task in the extraction of river networks from digital elevation models (DEMs). Several methods have been developed to extract river networks from Digital Elevation Models. However, few studies have considered the geomorphologic complexity in the FAT estimation and river network extraction. Recent studies estimated influencing factors’ impacts on the river length or drainage density without considering anthropogenic impacts and landscape patterns. This study contributes two FAT estimation methods. The first method explores the statistical association between FAT and 47 tentative explanatory factors. Specifically, multi-source data, including meteorologic, vegetation, anthropogenic, landscape, lithology, and topologic characteristics are incorporated into a drainage density-FAT model in basins with complex topographic and environmental characteristics. Non-negative matrix factorization (NMF) was employed to evaluate the factors’ predictive performance. The second method exploits fractal geometry theory to estimate the FAT at the regional scale, that is, in basins whose large areal extent precludes the use of basin-wide representative regression predictors. This paper’s methodology is applied to data acquired for Hubei and Qinghai Provinces, China, from 2001 through 2018 and systematically tested with visual and statistical criteria. Our results reveal key local features useful for river network extraction within the context of complex geomorphologic characteristics at relatively small spatial scales and establish the importance of properly choosing explanatory geomorphologic characteristics in river network extraction. The multifractal method exhibits more accurate extracting results than the box-counting method at the regional scale.

GIS based morphostratigraphic evaluation of glaciofluvial terraces in the foreland of the European Alps

2020 ◽  
Author(s):  
Thomas Pollhammer ◽  
Bernhard Salcher ◽  
Florian Kober ◽  
Gaudenz Deplazes
Keyword(s):  
High Resolution ◽  
Digital Elevation Models ◽  
Regional Scale ◽  
European Alps ◽  
Rhine River ◽  
Geological Evidence ◽  
The North ◽  
Digital Elevation ◽  
Stratigraphic Model ◽  
Alpine Foreland

<p>Glacial and glaciofluvial sediments of the North Alpine Foreland have been subject to extensive quaternary research for more than a century. Nevertheless, a regional scale stratigraphic model has not been proposed since Penk & Brückner (1909). Since then, geological evidence were fit into local stratigraphic classifications, leading to severe inconsistencies across different countries/regions. The following study aims to solve inconsistencies by a morphostratigraphical approach, applying innovative methods utilizing new high-resolution digital elevation models, existing geodata and information from literature.</p><p>First, the abundant information from literature was reviewed to create a synopsis of commonly used terrace stratigraphic classifications. Second, geologic maps and (high-resolution) digital elevation models were compiled in a GIS database. To process this data, a new toolset was developed (using software R), fitting the requirements of morphostratigraphic analyses. These mainly involve the processing and statistic evaluation of terrace-top surfaces. Based on these analyses, we discussed fluvial, glacial and geodynamic factors, controlling the observed hypsometric parameters (concavity, slope, relative heights). To stratigraphically compare results across catchments and regions, the modern Danube and Rhine River were used as “fixed” base-levels to which tributary terrace tops were extrapolated. Terrace elevations above these base-levels were used as proxy to evaluate the rare absolute and otherwise inferred terrace ages from literature. Derived morphostratigraphic evidence provides an objective basis to discuss and harmonise the highly complex and diverging stratigraphic classification schemes across North Alpine Foreland regions.</p><p>Penck, A., & Brückner, E. (1909). Die Alpen im Eiszeitalter. Leipzig: Tauchnitz.</p>

scholarly journals EVALUATION OF DIGITAL ELEVATION MODELS FOR GEOMORPHOMETRIC ANALYSES ON DIFFERENT SCALES FOR NORTHERN CHILE

2019 ◽  
Vol XLII-2/W13 ◽  
pp. 1229-1235 ◽  
Author(s):  
T. Kramm ◽  
D. Hoffmeister
Keyword(s):  
High Resolution ◽  
Satellite Imagery ◽  
Large Scale ◽  
Thermal Emission ◽  
Digital Elevation Models ◽  
Regional Scale ◽  
Laser Altimeter ◽  
Absolute Deviation ◽  
Digital Elevation ◽  
Very High

<p><strong>Abstract.</strong> The resolution and accuracy of digital elevation models (DEMs) have direct influence on further geoscientific computations like landform classifications and hydrologic modelling results. Thus, it is crucial to analyse the accuracy of DEMs to select the most suitable elevation model regarding aim, accuracy and scale of the study. Nowadays several worldwide DEMs are available, as well as DEMs covering regional or local extents. In this study a variety of globally available elevation models were evaluated for an area of about 190,000&amp;thinsp;km<sup>2</sup>. Data from Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) 30 m, Shuttle Radar Topography Mission (SRTM) 30&amp;thinsp;m and 90&amp;thinsp;m, Advanced Land Observing Satellite (ALOS) World 3D 30&amp;thinsp;m and TanDEM-X WorldDEM&amp;trade; &amp;ndash; 12&amp;thinsp;m and 90&amp;thinsp;m resolution were obtained. Additionally, several very high resolution DEM data were derived from stereo satellite imagery from SPOT 6/7 and Pléiades for smaller areas of about 100&amp;ndash;400&amp;thinsp;km<sup>2</sup> for each dataset. All datasets were evaluated with height points of the Geoscience Laser Altimeter System (GLAS) instrument aboard the NASA Ice, Cloud, and land Elevation (ICESat) satellite on a regional scale and with nine very high resolution elevation models from UAV-based photogrammetry on a very large scale. For all datasets the root mean square error (RMSE) and normalized median absolute deviation (NMAD) was calculated. Furthermore, the association of errors to specific terrain was conducted by assigning these errors to landforms from the topographic position index (TPI), topographic roughness index (TRI) and slope. For all datasets with a global availability the results show the highest overall accuracies for the TanDEM-X 12&amp;thinsp;m (RMSE: 2.3&amp;thinsp;m, NMAD: 0.8&amp;thinsp;m). The lowest accuracies were detected for the 30&amp;thinsp;m ASTER GDEM v3 (RMSE: 8.9&amp;thinsp;m, NMAD: 7.1&amp;thinsp;m). Depending on the landscape the accuracies are higher for all DEMs in flat landscapes and the errors rise significantly in rougher terrain. Local scale DEMs derived from stereo satellite imagery show a varying overall accuracy, mainly depending on the topography covered by the scene.</p>

APPLICATION OF THE GROUND LASER SCANNING RESULTS IN MONITORING OF ADJACENT ROCK MASSES OF DEEP CAREERS

2020 ◽  
Vol 2020 (4) ◽  
pp. 79-86
Author(s):  
Sh Rahimov ◽  
Keyword(s):  
Comparative Analysis ◽  
Laser Scanning ◽  
Digital Elevation Models ◽  
Satellite Observations ◽  
Control Points ◽  
Rock Masses ◽  
Digital Elevation ◽  
Instrumental Observations ◽  
Mine Surveying ◽  
Adjacent Rock

The method of laser scanning, used in combination with the traditional mine surveying, is one of the most effective and safest ways to carry out mine surveying and instrumental observations on deforming areas of open mining objects. The article presents the results of ground-based laser scanning of the Kharanutsky coal pit and a comparative analysis to determine the deformations and displacements of the sides for different periods, which was performed in the RISCAN PRO environment. Digital elevation models (DEM) were built, distinguishing observation cycles by color. As a result of comparison, the places of manifestation of deformations and displacements were revealed. Based on the results of geomonitoring, it was concluded that critical displacements and deformations were not detected, despite the places where small rockslides were manifested, and further systematic observations were recommended. The results of laser scanning are confirmed by the data of satellite observations on the control points and the survey of the section sides

scholarly journals Digital Elevation Models of Rockfalls and Landslides: A Review and Meta-Analysis

Geosciences ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 256
Author(s):  
Maria P. Kakavas ◽  
Konstantinos G. Nikolakopoulos
Keyword(s):  
High Resolution ◽  
Spatial Resolution ◽  
Structural Characteristics ◽  
Digital Elevation Models ◽  
Meta Analysis ◽  
Regional Scale ◽  
Major Question ◽  
Medium Resolution ◽  
Digital Elevation ◽  
Landslide Event

The scope of this paper is to summarize previous research pertaining to the use of digital elevation models (DEMs) and digital terrain models (DTMs) in the study of rockfalls and landslides. Research from 1983 to 2020 was surveyed in order to understand how the spatial resolution of DEMs and DTMs affects landslide detection, validation, and mapping. Another major question examined was the relationship between the DEM resolution and the extent of the rockfall or landslide event. It emerged from the study that, for landslides, the majority of researchers used DEMs with a spatial resolution of between 10 m and 30 m, while for rockfalls, they used DEMs with a spatial resolution of between 5 m and 20 m. We concluded that DEMs with a very high resolution (less than 5 m) are suitable for local-scale occurrences, while medium-resolution (from 20 m to 30 m) DEMs are suitable for regional-scale events. High resolution is associated with high accuracy and detailed structural characteristics, while medium accuracy better illustrates the topographic features. A low pixel size (more than 90 m) is not recommended for this type of research. Susceptibility maps, inventory maps, hazard risk zones, and vulnerability assessments are some of the main tools used in landslide/rockfall investigations, and topographic indexes, methods, models, and software optimize the reliability of the results. All of these parameters are closely related to DEMs and DTMs as the cell size affects the credibility of the final outcome.

Digital Elevation Models

10.1596/34445 ◽  
2020 ◽  
Author(s):  
Louise Croneborg ◽  
Keiko Saito ◽  
Michel Matera ◽  
Don McKeown ◽  
Jan van Aardt
Keyword(s):  
Digital Elevation Models ◽  
Digital Elevation
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