Analysis of Factors Triggering Shallow Failure and Deep-Seated Landslides Induced by Single Rainfall Events

2015 ◽  
Vol 10 (5) ◽  
pp. 966-972 ◽  
Author(s):  
Teng-To Yu ◽  
◽  
Ting-Shiuan Wang ◽  
Youg-Sin Cheng
Keyword(s):  
Digital Terrain Model ◽  
Landslide Risk ◽  
Index Method ◽  
Rainfall Events ◽  
Terrain Model ◽  
Digital Terrain ◽  
Accumulated Rainfall ◽  
Shallow Failure ◽  
Risk Potential

Earthquakes, rainfall, or a combination of both can trigger landslides, which can be classified into shallow and deep-seated types according to scale. Landslide risk potential can be charted according to the spatiotemporal characteristics of a combination of triggering factors that can be collated for similar historical events by various methods. The geographic information system (GIS) and the instability index method are two approaches commonly used to perform such a task; however, the nature of the event and the quality of imported data affect the degree of bias of model predictions against real-time values. To identify the differences between shallow and deep-seated landslides, 324 cases of landslides triggered by single rainfall events in Taiwan are analyzed in this study. It is determined that the principal factor governing shallow failure for rainfall-induced landslides is slope and that deep-seated failure is controlled by the amount of accumulated rainfall. By arranging the weighting, these factors could predict 93% and 75% of the occurrences of shallow and deep-seated landslides, respectively, based on a pre-event digital terrain model.

scholarly journals ASSESSMENT OF THE QUALITY OF DIGITAL TERRAIN MODEL PRODUCED FROM UNMANNED AERIAL SYSTEM IMAGERY

2016 ◽  
Vol XLI-B1 ◽  
pp. 893-899
Author(s):  
M. Kosmatin Fras ◽  
A. Kerin ◽  
M. Mesarič ◽  
V. Peterman ◽  
D. Grigillo
Keyword(s):  
Quality Assessment ◽  
Point Cloud ◽  
Digital Terrain Model ◽  
Quality Parameter ◽  
Unmanned Aerial System ◽  
Test Field ◽  
Absolute Deviation ◽  
Terrain Model ◽  
Digital Terrain

Production of digital terrain model (DTM) is one of the most usual tasks when processing photogrammetric point cloud generated from Unmanned Aerial System (UAS) imagery. The quality of the DTM produced in this way depends on different factors: the quality of imagery, image orientation and camera calibration, point cloud filtering, interpolation methods etc. However, the assessment of the real quality of DTM is very important for its further use and applications. In this paper we first describe the main steps of UAS imagery acquisition and processing based on practical test field survey and data. The main focus of this paper is to present the approach to DTM quality assessment and to give a practical example on the test field data. For data processing and DTM quality assessment presented in this paper mainly the in-house developed computer programs have been used. The quality of DTM comprises its accuracy, density, and completeness. Different accuracy measures like RMSE, median, normalized median absolute deviation and their confidence interval, quantiles are computed. The completeness of the DTM is very often overlooked quality parameter, but when DTM is produced from the point cloud this should not be neglected as some areas might be very sparsely covered by points. The original density is presented with density plot or map. The completeness is presented by the map of point density and the map of distances between grid points and terrain points. The results in the test area show great potential of the DTM produced from UAS imagery, in the sense of detailed representation of the terrain as well as good height accuracy.

scholarly journals Threat of Pollution Hotspots Reworking in River Systems: Case Study of the Ploučnice River (Czech Republic)

2019 ◽  
Vol 8 (1) ◽  
pp. 37 ◽  
Author(s):  
Jitka Elznicová ◽  
Tomáš Matys Grygar ◽  
Jan Popelka ◽  
Martin Sikora ◽  
Petr Novák ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Digital Terrain Model ◽  
Terrain Model ◽  
Non Invasive ◽  
Digital Terrain ◽  
Quality Of Water ◽  
Lateral Channel ◽  
Floodplain Development ◽  
Channel Deposits

As fluvial pollution may endanger the quality of water and solids transported by rivers, mapping and evaluation of historically polluted fluvial sediments is an urgent topic. The Ploučnice River and its floodplain were polluted by local uranium mining from 1971–1989. We have studied this river since 2013 using a combination of diverse methods, including geoinformatics, to identify pollution hotspots in floodplains and to evaluate the potential for future reworking. Archival information on pollution history and past flooding was collected to understand floodplain dynamics and pollution heterogeneity. Subsequently, a digital terrain model based on laser scanning data and data analysis were used to identify the sites with river channel shifts. Finally, non-invasive geochemical mapping was employed, using portable X-ray fluorescence and gamma spectrometers. The resulting datasets were processed with geostatistical tools. One of the main outputs of the study was a detailed map of pollution distribution in the floodplain. The results showed a relationship between polluted sediment deposition, past channel shifts and floodplain development. We found that increased concentration of pollution occurred mainly in the cut-off meanders and lateral channel deposits from the mining period, the latter in danger of reworking (reconnecting to the river) in the coming decades.

scholarly journals Can analytical shading be art?

2015 ◽  
Vol 47 (3) ◽  
pp. 121-135
Author(s):  
Jerzy Siwek ◽  
Wojciech Wacławik
Keyword(s):  
Experimental Studies ◽  
Digital Terrain Model ◽  
Crucial Importance ◽  
Significant Similarity ◽  
Basic Principles ◽  
Factors Affecting ◽  
Terrain Model ◽  
Digital Terrain ◽  
Proper Generalization

Abstract Despite numerous theoretical and experimental studies of analytical relief shading, devised about half a century ago, its quality has not yet reached the excellence of traditional (manual) shading. The paper discusses its basic principles and the main factors affecting the quality of shading. It also stresses the crucial importance of the digital terrain model used as the basis for shading as well as the proper generalization of the relief. Experiments with shading modules of ArcGIS and Surfer, aiming to explore the functionality of algorithms they employ, have demonstrated significant similarity of the results. In conclusion, the authors attempt to answer the question posted in the title of the article. In their view, analytical shading is not art because shading algorithms are incapable of producing the visually beautiful effects that an experienced cartographer with artistic talents can create.

scholarly journals Analysis of the current state of unstable geomorphological structures with modern methods

2020 ◽  
Vol 13 (1) ◽  
pp. 195-199
Author(s):  
Vyacheslav V. Dolotov ◽  
Yuri N. Goryachkin ◽  
Andrey V. Dolotov
Keyword(s):  
Time Perspective ◽  
Digital Terrain Model ◽  
Aerial Photographs ◽  
Detailed Data ◽  
Terrain Model ◽  
Digital Terrain ◽  
Current State ◽  
The Status ◽  
The Mathematical Model

The paper gives results of the digitization of the status and spatial position of a cliff in the Western Crimea coastal zone. The modern equipment and methods accelerate the survey from the time perspective and improve the quality of the outcomes; namely a high precision GNSS receiver in RTK mode and PHANTOM-3 PRO copter. The digital terrain model was generated with used the Agisoft Photoscan software. The paper shows that the precision of the mathematical model of the relief constructed by aerial photographs provides more detailed data in comparison to those obtained in the field observations. Furthermore, aerial photography makes it possible to calculate the number of spatial characteristics of hazardous for surveying and latent natural objects out of reach for an on-location investigation. As a result, the very detailed data about current condition of dangerous cliff were obtained. The paper also evaluates the linear and volumetric characteristics of cleavages that are prone to collapse.

scholarly journals ACCURACY ASSESSMENT OF LIDAR-DERIVED DIGITAL TERRAIN MODEL (DTM) WITH DIFFERENT SLOPE AND CANOPY COVER IN TROPICAL FOREST REGION

2015 ◽  
Vol II-2/W2 ◽  
pp. 183-189 ◽  
Author(s):  
M. R. M. Salleh ◽  
Z. Ismail ◽  
M. Z. A. Rahman
Keyword(s):  
Tropical Forest ◽  
Digital Terrain Model ◽  
Canopy Cover ◽  
Airborne Lidar ◽  
Lidar Data ◽  
Terrain Model ◽  
Digital Terrain ◽  
Terrain Slope ◽  
Airborne Lidar Data

Airborne Light Detection and Ranging (LiDAR) technology has been widely used recent years especially in generating high accuracy of Digital Terrain Model (DTM). High density and good quality of airborne LiDAR data promises a high quality of DTM. This study focussing on the analysing the error associated with the density of vegetation cover (canopy cover) and terrain slope in a LiDAR derived-DTM value in a tropical forest environment in Bentong, State of Pahang, Malaysia. Airborne LiDAR data were collected can be consider as low density captured by Reigl system mounted on an aircraft. The ground filtering procedure use adaptive triangulation irregular network (ATIN) algorithm technique in producing ground points. Next, the ground control points (GCPs) used in generating the reference DTM and these DTM was used for slope classification and the point clouds belong to non-ground are then used in determining the relative percentage of canopy cover. The results show that terrain slope has high correlation for both study area (0.993 and 0.870) with the RMSE of the LiDAR-derived DTM. This is similar to canopy cover where high value of correlation (0.989 and 0.924) obtained. This indicates that the accuracy of airborne LiDAR-derived DTM is significantly affected by terrain slope and canopy caver of study area.

scholarly journals PREPROCESSING OF SATELLITE DATA FOR URBAN OBJECT EXTRACTION

2015 ◽  
Vol XL-3/W2 ◽  
pp. 115-120 ◽  
Author(s):  
T. Krauß
Keyword(s):  
Digital Terrain Model ◽  
Stereo Pair ◽  
Spectral Classification ◽  
Terrain Model ◽  
Digital Terrain ◽  
Digital Elevation ◽  
Elevation Model ◽  
Processing Steps

Very high resolution (VHR) DSMs (digital surface models) derived from stereo- or multi-stereo images from current VHR satellites like WorldView-2 or Pléiades can be produced up to the ground sampling distance (GSD) of the sensors in the range of 50 cm to 1 m. From such DSMs the digital terrain model (DTM) representing the ground and also a so called nDEM (normalized digital elevation model) describing the height of objects above the ground can be derived. In parallel these sensors deliver multispectral imagery which can be used for a spectral classification of the imagery. Fusion of the multispectral classification and the nDEM allows a simple classification and detection of urban objects. In further processing steps these detected urban objects can be modeled and exported in a suitable description language like CityGML. In this work we present the pre-processing steps up to the classification and detection of the urban objects. The modeling is not part of this work. The pre-processing steps described here cover briefly the coregistration of the input images and the generation of the DSM. In more detail the improvement of the DSM, the extraction of the DTM and nDEM, the multispectral classification and the object detection and extraction are explained. The methods described are applied to two test regions from two satellites: First the center of Munich acquired by WorldView-2 and second the center of Melbourne acquired by Pl´eiades. From both acquisitions a stereo-pair from the panchromatic bands is used for creation of the DSM and the pan-sharpened multispectral images are used for spectral classification. Finally the quality of the detected urban objects is discussed.

scholarly journals Comparison of methodologies for automatic generation of limits and drainage networks for hidrographic basins

2009 ◽  
Vol 13 (4) ◽  
pp. 369-375 ◽  
Author(s):  
Samantha A. Alcaraz ◽  
Christophe Sannier ◽  
Antonio C. T. Vitorino ◽  
Omar Daniel
Keyword(s):  
Digital Terrain Model ◽  
Automatic Generation ◽  
Geographical Information ◽  
Stream Network ◽  
Terrain Model ◽  
Digital Terrain ◽  
Contour Lines ◽  
Drainage Networks ◽  
Selection Of

The objective of this work was to compare methodologies for the automatic generation of limits and drainage networks, using a geographical information system for basins of low relief variation, such as the Dourados catchment area. Various data/processes were assessed, especially the ArcHydro and AVSWAT interfaces used to process 50 m resolution DTMs formed from the interpolation of digitalized contour lines using ArcInfo, ArcView and Spring GIS, and a 90 m resolution SRTM DTM acquired by interferometry radar. Their accuracy was estimated based upon the pre-processing of small basic sub-basin units of different relief variations, before applying the best combinations to the entire Dourados basin. The accuracy of the automatic stream network generation and watershed delineation depends essentially on the quality of the raw digital terrain model. The selection of the most suitable one then depends completely on the aims of the user and on the work scale.

scholarly journals Creation of the snow avalanche susceptibility map of the Krkonoše Mountains using GIS

2011 ◽  
Vol 59 (5) ◽  
pp. 237-246 ◽  
Author(s):  
Petr Suk ◽  
Martin Klimánek
Keyword(s):  
Morphological Characteristics ◽  
Digital Terrain Model ◽  
Snow Avalanche ◽  
Susceptibility Map ◽  
Aerial Photos ◽  
Terrain Model ◽  
Slope Steepness ◽  
Digital Terrain ◽  
Supervised Image Classification

This article deals with the development of the snow avalanche susceptibility map in the Czech part of the Krkonoše Mountains using the free Geographic Information System (GIS) GRASS. The area susceptibility map consists of two components: the morphological risk map, which is derived from the digital terrain model (DTM) and describes the slope steepness, aspect and curvature of the slope, and the protecting vegetation influence map, which is based on supervised image classification (spectrozonal aerial photos) and takes into consideration the importance of vegetation cover. The final map also includes starting zones calculated on the basis of significant changes in slope steepness and approximate shapes of avalanche paths based on these zones. In the map development, the layer of measured paths of avalanche cadastre in the Czech part of the Krkonoše Mountains was used, partly to gain the morphological characteristics of starting zones and partly to check the quality of the map.

scholarly journals FEATURES OF CONSTRUCTION OF DIGITAL RELIEF MODEL ACCORDING TO THE RESULTS OF GEODESIC SURVEYING LOCATIONS

2021 ◽  
Vol 1 (161) ◽  
pp. 104-108
Author(s):  
A. Batrakova ◽  
Y. Dorozhko ◽  
V. Yemets
Keyword(s):  
Surface Display ◽  
Digital Terrain Model ◽  
Topographic Maps ◽  
Surface Model ◽  
Terrain Model ◽  
Model Based ◽  
Digital Terrain ◽  
Geodetic Measurements ◽  
Geodetic Surveying

Topographic maps in digital and electronic forms are created on the basis of available paper topographic maps or on the basis of primary materials of geodetic surveys. Geodetic surveys are performed both by ground methods, without the use of photogrammetric materials, and on the basis of materials obtained as a result of ground phototheodolite or aerial photography. The construction of a digital terrain model is a multi-stage process, which consists of a significant number of interconnected operations performed at the stage of in-house processing of the results of geodetic measurements carried out during engineering and geodetic surveys. The quality of the final result of modeling depends on the quality of each stage of construction of a digital terrain model, so it is extremely important to pay attention to all technological processes of model construction. The digital relief model is considered as an ordered set of triangular faces constructed by the Delaunay algorithm. The main condition of this type of triangulation is that in the middle of the circle described around any triangle can not be the vertex of another triangle. Construction of a digital terrain model based on the results of geodetic surveying of the area in the general case can be divided into several stages. At the beginning, an automated construction of triangulation is performed on the basis of the results of geodetic measurements, which carry information about three-dimensional coordinates of survey points. Allotments adjust the display of horizontals. Regardless of the selected surface display style, the surface model is a grid of triangles. At the next stage of construction of the digital model of a relief carry out visual control of the created model and if necessary carry out editing of elements of a surface and change of position of edges of triangulation for change of position of horizontals. The last stage of building a digital terrain model based on the results of geodetic surveying of the area is the design of modeling results, the application of individual styles of reflection for individual areas of the surface and the creation of mountain strokes and signatures of horizontals.

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