scholarly journals Subaqueous geomorphology: options, tasks, needs

2019 ◽  
Vol 16 (1) ◽  
pp. 89-97
Author(s):  
Stanisław Rudowski ◽  
Radosław Wróblewski ◽  
Janusz Dworniczak ◽  
Kazimierz Szefler ◽  
Benedykt Hac ◽  
...  
Keyword(s):  
Land Surface ◽  
Digital Terrain Model ◽  
Side Scan Sonar ◽  
Multibeam Echosounder ◽  
Seismic Profiling ◽  
Terrain Model ◽  
Non Invasive ◽  
Digital Terrain ◽  
Surface Survey ◽  
Echo Sounder

Abstract The purpose of the paper is to present the potentialities of current non-invasive methods for bottom surveys, including cartometric presentation of its relief and structure in both marine and inland reservoirs. The paper presents examples of results obtained in the Maritime Institute in Gdańsk during surveys carried out at the bottom of seas, lakes and rivers with the use of the same apparatus: primarily, a multibeam echosounder (MBES) to obtain a digital terrain model (DTM); a side-scan sonar (SSS) to obtain a general image of the nature of the bottom (its “roughness”); and seismic profiling (sub-bottom profiler, sediment echo sounder [SES]) to recognise the structure of the bottom. The obtained results constitute a necessary basis for carrying out further specialist surveys (non-invasive or invasive) when needed. Current bottom survey options that use MBES, SSS and SES may be treated as subaqueous equivalents of the subaerial potentialities of a land surface survey using LiDaR and GPR (Ground Penetration Radar).

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 Evaluation of GIS techniques in digital terrain model with temporal data: an approach based in the slope of the land surface

2015 ◽  
Vol 11 (1) ◽  
Author(s):  
Luiz Gilberto Bertotti ◽  
Mauricio Camargo Filho ◽  
Marcos Aurélio Pelegrina ◽  
Marquiana Freitas Vilas Boas Gomes ◽  
Bruno Henrique Costa Toledo ◽  
...  
Keyword(s):  
Land Surface ◽  
Digital Terrain Model ◽  
Temporal Data ◽  
Terrain Model ◽  
Gis Techniques ◽  
Digital Terrain

scholarly journals Digital Modeling Phenomenon Of Surface Ground Movement

2016 ◽  
Vol 73 (2) ◽  
pp. 342
Author(s):  
Ioan Voina ◽  
Maricel Palamariu ◽  
Iohan Neuner ◽  
Tudor Salagean ◽  
Dumitru Onose ◽  
...  
Keyword(s):  
Land Surface ◽  
Interpolation Method ◽  
Digital Terrain Model ◽  
Industrial Applications ◽  
Ground Movement ◽  
Terrain Model ◽  
Software Applications ◽  
Specialized Software ◽  
Digital Terrain ◽  
Work Area

With the development of specialized software applications it was possible to approach and resolve complex problems concerning automating and process optimization for which are being used field data. Computerized representation of the shape and dimensions of the Earth requires a detailed mathematical modeling, known as "digital terrain model". The paper aims to present the digital terrain model of Vulcan mining, Hunedoara County, Romania. Modeling consists of a set of mathematical equations that define in detail the surface of Earth and has an approximate surface rigorously and mathematical, that calculated the land area. Therefore, the digital terrain model means a digital representation of the earth's surface through a mathematical model that approximates the land surface modeling, which can be used in various civil and industrial applications in. To achieve the digital terrain model of data recorded using linear and nonlinear interpolation method based on point survey which highlights the natural surface studied. Given the complexity of this work it is absolutely necessary to know in detail of all topographic elements of work area, without the actions to be undertaken to project and manipulate would not be possible. To achieve digital terrain model, within a specialized software were set appropriate parameters required to achieve this case study. After performing all steps we obtained digital terrain model of Vulcan Mine. Digital terrain model is the complex product, which has characteristics that are equivalent to the specialists that use satellite images and information stored in a digital model, this is easier to use.

scholarly journals Inverse distance weighting method optimization in the process of digital terrain model creation based on data collected from a multibeam echosounder

2020 ◽  
Vol 12 (4) ◽  
pp. 397-407
Author(s):  
Wojciech Maleika
Keyword(s):  
Measurement Data ◽  
Digital Terrain Model ◽  
Inverse Distance Weighting ◽  
Weighting Method ◽  
Calculation Time ◽  
Multibeam Echosounder ◽  
Terrain Model ◽  
Digital Terrain ◽  
Distance Weighting ◽  
Inverse Distance

Abstract This paper presents the optimization of the inverse distance weighting method (IDW) in the process of creating a digital terrain model (DTM) of the seabed based on bathymetric data collected using a multibeam echosounder (MBES). There are many different methods for processing irregular measurement data into a grid-based DTM, and the most popular of these methods are inverse distance weighting (IDW), nearest neighbour (NN), moving average (MA) and kriging (K). Kriging is often considered one of the best methods in interpolation of heterogeneous spatial data, but its use is burdened by a significantly long calculation time. In contrast, the MA method is the fastest, but the calculated models are less accurate. Between them is the IDW method, which gives satisfactory accuracy with a reasonable calculation time. In this study, the author optimized the IDW method used in the process of creating a DTM seabed based on measurement points from MBES. The goal of this optimization was to significantly accelerate the calculations, with a possible additional increase in the accuracy of the created model. Several variants of IDW methods were analysed (dependent on the search radius, number of points in the interpolation, power of the interpolation and applied smoothing method). Finally, the author proposed an optimization of the IDW method, which uses a new technique of choosing the nearest points during the interpolation process (named the growing radius). The experiments presented in the paper and the results obtained show the true potential of the IDW optimized method in the case of DTM estimation.

Integrating acoustics and photogrammetry-based 3D point clouds for the generation of a continuous bathymetric model in coral reef environment.

2020 ◽  
Author(s):  
Alessandra Savini ◽  
Fabio Marchese ◽  
Luca Fallati ◽  
Cesare Corselli ◽  
Paolo Galli
Keyword(s):  
Coral Reef ◽  
Reef Flat ◽  
Digital Terrain Model ◽  
Point Clouds ◽  
Multibeam Echosounder ◽  
Terrain Model ◽  
Digital Terrain ◽  
3D Point Clouds ◽  
Reef Environments ◽  
Elevation Data

<p>Digital terrain model (DTM) reconstruction in coral reef environments through traditional mapping methods, using either singlebeam or multibeam echosounder systems, often presents difficulties in obtaining a continuous 3-dimensional representation, due to the complex topography and the considerable extension of very shallow areas (i.e. reef flat areas). The present-day most advanced techniques used to collect high-resolution elevation data both for land surface and the seafloor, in coral reef environments, include the use of satellite-derived bathymetry, LIDAR technology, Unmanned Aerial Vehicles coupled with photogrammetry and traditional bathymetric surveys. Data processing represents in all the cases a fundamental step for ensuring the accuracy and reliability of obtained measurements, especially for allowing a precise integration of all data sources into a continuous DTM. In our work, we present a tested methodological protocol for the generation of a continuous fine-scale digital terrain model (DTM) in coral reef environments. A portion of an atoll reef (Magoodhoo reef located in the Maldivian archipelago, the southern part of Faafu atoll) has been remotely mapped from the reef flat area to the connected and deeper lagoon environment, collecting elevation data by different sources according to the surveyed depths. In particular, we acquired acoustic depth measurements using a multibeam echosounder and 3D point clouds applying the Structure from Motion (SfM) technique to RGB images, collected using an Unmanned Aerial Vehicle (UAV). All obtained data were calibrated and validated with RTK-GNSS measurements and successfully integrated in order to generate a harmonized DTM for the surveyed sector of the Magoodhoo reef.</p>

scholarly journals PENERAPAN METODE MOVING AVERAGE DAN DIGITAL TERRAIN MODEL (DTM) UNTUK VISUALISASI BATIMETRI 3 DIMENSI DATA MULTIBEAM ECHOSOUNDER

2017 ◽  
Vol 7 (2) ◽  
pp. 117-124
Author(s):  
Fahrulian Fahrulian ◽  
Henry M Manik ◽  
Indra Jaya
Keyword(s):  
Moving Average ◽  
Digital Terrain Model ◽  
Multibeam Echosounder ◽  
Terrain Model ◽  
Digital Terrain

Data dan informasi mengenai bentuk topografi dasar laut sangat penting, antara lain untuk kepentingan kemanan pelayaran dan juga penting untuk kajian strategis lainnya. Makalah ini menjelaskan tentang kombinasi data multibeam echosoder dan metode Digital Terrain Model (DTM) untuk melihat kenampakan dasar laut. Metode moving average dipilih karena sangat cocok untuk diterapkan pada data multibeam yang berjumlah banyak. Hasil akhir dari kombinasi dua metode tersebut adalah visualisasi 3 dimensi. Metode ini menggunakan data multibeam echosounder yang telah dikoreksi dan diawali proses pembentukan gridding yang mewakili nilai-nilai yang ada disepanjang lajur survei. Nilai dari masing-masing gridding akan membentuk sebaran nilai seluruh data sounding. shadding relief dan visualisasi wireframe sheet menjadi kunci untuk membangun sebuah  DTM. Proses penggabungan layer yang ada digunakan untuk melihat kenampakan secara halus melalui penerapan pengaturan pencahayaan sehingga akan menghasilkan citra yang lebih halus. Analisis sederhana mengenai kemiringan (slope) dapat terlihat dengan adanya hasil DTM ini.

scholarly journals Digital Terrain Models Generated with Low-Cost UAV Photogrammetry: Methodology and Accuracy

2021 ◽  
Vol 10 (5) ◽  
pp. 285
Author(s):  
Sergio Iván Jiménez-Jiménez ◽  
Waldo Ojeda-Bustamante ◽  
Mariana Marcial-Pablo ◽  
Juan Enciso
Keyword(s):  
Land Surface ◽  
Survey Methods ◽  
Low Cost ◽  
Digital Terrain Model ◽  
High Accuracy ◽  
Digital Cameras ◽  
Ground Sample ◽  
Terrain Model ◽  
Digital Terrain ◽  
Dense Point

Digital terrain model (DTM) generation is essential to recreating terrain morphology once the external elements are removed. Traditional survey methods are still used to collect accurate geographic data on the land surface. Given the emergence of unmanned aerial vehicles (UAVs) equipped with low-cost digital cameras and better photogrammetric methods for digital mapping, efficient approaches are necessary to allow rapid land surveys with high accuracy. This paper provides a review, complemented with the authors’ experience, regarding the UAV photogrammetric process and field survey parameters for DTM generation using popular commercial photogrammetric software to process images obtained with fixed-wing or multicopter UAVs. We analyzed the quality and accuracy of the DTMs based on four categories: (i) the UAV system (UAV platforms and camera); (ii) flight planning and image acquisition (flight altitude, image overlap, UAV speed, orientation of the flight line, camera configuration, and georeferencing); (iii) photogrammetric DTM generation (software, image alignment, dense point cloud generation, and ground filtering); (iv) geomorphology and land use/cover. For flat terrain, UAV photogrammetry provided a horizontal root mean square error (RMSE) between 1 to 3 × the ground sample distance (GSD) and a vertical RMSE between 1 to 4.5 × GSD, and, for complex topography, a horizontal RMSE between 1 to 7 × GSD and a vertical RMSE between 1.5 to 5 × GSD. Finally, we stress that UAV photogrammetry can provide DTMs with high accuracy when the photogrammetric process variables are optimized.

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