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 Investigating the Impact of Digital Elevation Models on Sentinel-1 Backscatter and Coherence Observations

2020 ◽  
Vol 12 (18) ◽  
pp. 3016
Author(s):  
Ignacio Borlaf-Mena ◽  
Maurizio Santoro ◽  
Ludovic Villard ◽  
Ovidiu Badea ◽  
Mihai Andrei Tanase
Keyword(s):  
Remote Sensing ◽  
Laser Scanning ◽  
Digital Elevation Models ◽  
Shuttle Radar Topography Mission ◽  
Synthetic Aperture ◽  
Mountainous Regions ◽  
Aerial Laser Scanning ◽  
Digital Elevation ◽  
The Difference ◽  
The Impact

Spaceborne remote sensing can track ecosystems changes thanks to continuous and systematic coverage at short revisit intervals. Active remote sensing from synthetic aperture radar (SAR) sensors allows day and night imaging as they are not affected by cloud cover and solar illumination and can capture unique information about its targets. However, SAR observations are affected by the coupled effect of viewing geometry and terrain topography. The study aims to assess the impact of global digital elevation models (DEMs) on the normalization of Sentinel-1 backscattered intensity and interferometric coherence. For each DEM, we analyzed the difference between orbit tracks, the difference with results obtained with a high-resolution local DEM, and the impact on land cover classification. Tests were carried out at two sites located in mountainous regions in Romania and Spain using the SRTM (Shuttle Radar Topography Mission, 30 m), AW3D (ALOS (Advanced Land Observation Satellite) World 3D, 30 m), TanDEM-X (12.5, 30, 90 m), and Spain national ALS (aerial laser scanning) based DEM (5 m resolution). The TanDEM-X DEM was the global DEM most suitable for topographic normalization, since it provided the smallest differences between orbital tracks, up to 3.5 dB smaller than with other DEMs for peak landform, and 1.4–1.9 dB for pit and valley landforms.

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 COMPARISON BETWEEN ABSOLUTE AND RELATIVE POSITIONAL ACCURACY ASSESSMENT - A CASE STUDY APPLIED TO DIGITAL ELEVATION MODELS

2019 ◽  
Vol 25 (1) ◽  
Author(s):  
Leandro Luiz Silva de França ◽  
Alex de Lima Teodoro da Penha ◽  
João Alberto Batista de Carvalho
Keyword(s):  
Thermal Emission ◽  
Accuracy Assessment ◽  
Digital Elevation Models ◽  
Shuttle Radar Topography Mission ◽  
Control Points ◽  
Positional Accuracy ◽  
Digital Elevation ◽  
The Absolute ◽  
Better Than

Abstract This paper presents a comparative study between the absolute and relative methods for altimetric positional accuracy of Digital Elevation Models (DEM). For the theoretical basis of this research, the definitions of accuracy (exactness) and precision, as well the concepts related to absolute and relative positional accuracy were explored. In the case study, the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and the Shuttle Radar Topography Mission (SRTM) DEM were used. In the analysis of the absolute accuracy, 6,568 ground control points from GNSS orbital survey were used, collected through relative-static method. In the relative accuracy, it was used as reference DEM with spatial resolution of 5 meters generated by stereophotogrammetrical process for the Mapping Project of Bahia (Brazil). It was concluded that, once the accuracy of the reference DEM is better than the other two evaluated DEM, the results of the classification for the PEC-PCD for the relative evaluation are equal to or better than the absolute evaluation results, with the advantage to being able to verify the pixel population of the evaluated models, which makes it possible to identify outliers, distortions and displacements, including delimiting regions, which is much less likely with a limited set of control points.

scholarly journals Data Gap Classification for Terrestrial Laser Scanning-Derived Digital Elevation Models

2020 ◽  
Vol 9 (12) ◽  
pp. 749
Author(s):  
Matthew S. O’Banion ◽  
Michael J. Olsen ◽  
Jeff P. Hollenbeck ◽  
William C. Wright
Keyword(s):  
Laser Scanning ◽  
Digital Elevation Models ◽  
Relative Proportion ◽  
Terrestrial Laser Scanning ◽  
Habitat Modeling ◽  
Rocky Intertidal ◽  
Intertidal Environment ◽  
Survey Quality ◽  
Digital Elevation ◽  
Data Gap

Extensive gaps in terrestrial laser scanning (TLS) point cloud data can primarily be classified into two categories: occlusions and dropouts. These gaps adversely affect derived products such as 3D surface models and digital elevation models (DEMs), requiring interpolation to produce a spatially continuous surface for many types of analyses. Ultimately, the relative proportion of occlusions in a TLS survey is an indicator of the survey quality. Recognizing that regions of a scanned scene occluded from one scan position are likely visible from another point of view, a prevalence of occlusions can indicate an insufficient number of scans and/or poor scanner placement. Conversely, a prevalence of dropouts is ordinarily not indicative of survey quality, as a scanner operator cannot usually control the presence of specular reflective or absorbent surfaces in a scanned scene. To this end, this manuscript presents a novel methodology to determine data completeness by properly classifying and quantifying the proportion of the site that consists of point returns and the two types of data gaps. Knowledge of the data gap origin can not only facilitate the judgement of TLS survey quality, but it can also identify pooled water when water reflections are the main source of dropouts in a scene, which is important for ecological research, such as habitat modeling. The proposed data gap classification methodology was successfully applied to DEMs for two study sites: (1) A controlled test site established by the authors for the proof of concept of classification of occlusions and dropouts and (2) a rocky intertidal environment (Rabbit Rock) presenting immense challenges to develop a topographic model due to significant tidal fluctuations, pooled water bodies, and rugged terrain generating many occlusions.

Accuracy of UAV-Based Digital Elevation Models

2021 ◽  
pp. 478-519
Author(s):  
Engelberth Soto-Estrada ◽  
Ann Wellens ◽  
Andrés Pava-Restrepo ◽  
Camilo Hernández Mejía
Keyword(s):  
Statistical Analysis ◽  
Land Cover ◽  
Information Acquisition ◽  
Digital Elevation Models ◽  
Control Points ◽  
Multiple Factors ◽  
Ground Control Points ◽  
Digital Elevation ◽  
Insufficient Number

UAV photogrammetry has simplified the measurement of the terrain's surface; however, the accuracy of the method is still a matter of research as it depends on multiple factors such as the UAV employed and the decisions made by the user during information acquisition and processing. This chapter analyses the accuracy of 27 digital elevation models (DEMs) built from the data acquired with a DJI Phantom 3 drone, which was flown at different heights and trajectories in a case study in the Colombian Department of Antioquia. The statistical analysis confirmed that the use of ground control points (GCPs) is fundamental to increase the accuracy of the map products. It also showed that accuracy, understood as the comparison between the coordinates of points measured in the field (CPs) with their corresponding values estimated in the orthophotomosaics, depends on the number of CPs and their location. An insufficient number of CPs or an inadequate distribution, for instance all or most of them located in a single land cover, will cause the accuracy to be overestimated.

scholarly journals A Relief Dependent Evaluation of Digital Elevation Models on Different Scales for Northern Chile

2019 ◽  
Vol 8 (10) ◽  
pp. 430 ◽  
Author(s):  
Kramm ◽  
Hoffmeister
Keyword(s):  
High Resolution ◽  
Laser Scanning ◽  
Thermal Emission ◽  
Comprehensive Evaluation ◽  
Digital Elevation Models ◽  
Shuttle Radar Topography Mission ◽  
Northern Chile ◽  
Digital Elevation ◽  
Elevation Data ◽  
Position Index

Many geoscientific computations are directly influenced by the resolution and accuracy of digital elevation models (DEMs). Therefore, knowledge about the accuracy of DEMs is essential to avoid misleading results. In this study, a comprehensive evaluation of the vertical accuracy of globally available DEMs from Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), Shuttle Radar Topography Mission (SRTM), Advanced Land Observing Satellite (ALOS) World 3D and TanDEM-X WorldDEM™ was conducted for a large region in Northern Chile. Additionally, several very high-resolution DEM datasets were derived from Satellite Pour l’Observation de la Terre (SPOT) 6/7 and Pléiades stereo satellite imagery for smaller areas. All datasets were evaluated with three reference datasets, namely elevation points from both Ice, Cloud, and land Elevation (ICESat) satellites, as well as very accurate high-resolution elevation data derived by unmanned aerial vehicle (UAV)-based photogrammetry and terrestrial laser scanning (TLS). The accuracy was also evaluated with regard to the existing relief by relating the accuracy results to slope, terrain ruggedness index (TRI) and topographic position index (TPI). For all datasets with global availability, the highest overall accuracies are reached by TanDEM-X WorldDEM™ and the lowest by ASTER Global DEM (GDEM). On the local scale, Pléiades DEMs showed a slightly higher accuracy as SPOT imagery. Generally, accuracy highly depends on topography and the error is rising up to four times for high resolution DEMs and up to eight times for low-resolution DEMs in steeply sloped terrain compared to flat landscapes.

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