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 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 Asymmetric Craters on the Dwarf Planet Ceres—Results of Second Extended Mission Data Analysis

Geosciences ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 475
Author(s):  
Katrin Krohn ◽  
Ralf Jaumann ◽  
Kai Wickhusen ◽  
Katharina Otto ◽  
Elke Kersten ◽  
...  
Keyword(s):  
Data Analysis ◽  
High Resolution ◽  
Morphological Characteristics ◽  
Digital Terrain Model ◽  
Successful Operation ◽  
Terrain Model ◽  
Digital Terrain ◽  
High Resolution Images ◽  
Sloping Surface

After almost three years of successful operation on Ceres, the Dawn spacecraft entered its last orbits around the dwarf planet and obtained a set of high-resolution images of 3 to 5 m/pixel. These images reveal a variety of morphologic features, including a set of asymmetric crater morphologies as observed earlier in the mission on the asteroid Vesta. We identified 269 craters, which are located between 60° N to 60° S latitude and 197° E to 265° E longitude, and investigated their morphological characteristics using a digital terrain model (DTM). These craters range in diameter from 0.30 to 4.2 km, and exhibit a sharp crater rim on the uphill side and a smooth one on the downhill side. We found that all asymmetric craters are formed on a sloping surface with the majority appearing at slope angles between 5 and 20 degrees. This implies that, as observed on Vesta, the topography is the main cause for these asymmetries.

Geomorphological conditions of snow avalanches in the Tatra Mountains

2016 ◽  
Vol 60 (4) ◽  
pp. 285-297 ◽  
Author(s):  
Zofia Rączkowska ◽  
Michał Długosz ◽  
Elżbieta Rojan
Keyword(s):  
Digital Terrain Model ◽  
Snow Avalanche ◽  
Slope Aspect ◽  
Snow Avalanches ◽  
Tatra Mountains ◽  
Aerial Photos ◽  
Slope Inclination ◽  
Terrain Model ◽  
The Tatra Mountains ◽  
The High Tatras

Snow avalanches are substantial processes of the natural environment and the denudation system in high mountains, with their activity depending on topoclimate, relief and snow conditions. The aim of the present research was to recognise the geomorphological conditions for snow avalanche activity in the Tatra Mountains by analysing the relationship between relief and avalanche path features for the area encompassing the whole of the massif – both the Polish and Slovak parts of the Tatras. Maps of snow avalanches that occurred in the recent past, aerial photos and a digital terrain model were used to make a map of avalanche paths, with the starting zone, avalanche track and accumulation zone specified within each snow avalanche path. For each type of designated unit of snow avalanche track, a morphometric analysis was performed, taking into account slope aspect and inclination. More than 3,770 avalanche paths were identified whose number, morphometric features and altitudinal range differ between individual parts of the Tatra Mountains, corresponding to relief. The length of avalanche paths reaches up to 3,138 m, with paths located about 200 m higher in the High Tatras than in other parts of the massif. The average area of the starting zone in the High Tatras is half the size of that in the Western Tatras, while the number of accumulation zones is double the size. Based on a statistical analysis, the interrelations between slope exposure, slope inclination and length of avalanche path, as well as size of starting zones, were established. It was found that the length of avalanche tracks and the size of avalanche starting zones both decrease with increasing slope inclination.

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 Correlation among Earthwork and Cropmark Anomalies within Archaeological Landscape Investigation by Using LiDAR and Multispectral Technologies from UAV

Drones ◽  
2020 ◽  
Vol 4 (4) ◽  
pp. 72
Author(s):  
Diego Ronchi ◽  
Marco Limongiello ◽  
Salvatore Barba
Keyword(s):  
Vegetation Indices ◽  
Three Dimensional ◽  
Digital Terrain Model ◽  
Buried Structures ◽  
Aerial Photos ◽  
Terrain Model ◽  
Survey Techniques ◽  
Digital Terrain ◽  
Vegetation Maps ◽  
The One

This project aimed to systematically investigate the archaeological remains of the imperial Domitian villa in Sabaudia (Italy), using different three-dimensional survey techniques. Particular attention in the research was paid to the identification and documentation of traces that buried structures left on the surface occupied by the villa, which extended for 46 hectares, an area that was fully covered with structures. Since a dense pine forest was planted during the 1940s and is currently covering the site, this contribution investigates particularly the correlation among the presence of cropmarks, identifiable with the processing of multispectral maps and vegetation indices from RGB images, and earthwork anomalies identified in a Digital Terrain Model (DTM) built, by utilizing a light detection and ranging (LiDAR) flight from an Unmanned Aerial Vehicle (UAV). The study demonstrates how the use of vegetation maps—calculated starting from RGB and multispectral aerial photos—can provide a more expeditious preliminary analysis on the position and extension of areas characterized by the presence of buried structures, but also that, in order to investigate in-depth a context in similar conditions, the most effective approach remains the one based on LiDAR technology. The integration between the two techniques may prove fruitful in limiting the extension of the areas to be investigated with terrestrial survey techniques.

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