scholarly journals Nation-wide, general-purpose delineation of geomorphological slope units in Italy

2018 ◽  
Author(s):  
Massimiliano Alvioli ◽  
Ivan Marchesini ◽  
Fausto Guzzetti
Keyword(s):  
Adaptive Algorithm ◽  
Central Italy ◽  
Optimization Procedure ◽  
General Purpose ◽  
General Requirement ◽  
Italian Peninsula ◽  
Slope Unit ◽  
Digital Elevation ◽  
Elevation Model ◽  
Definition Of

Slope units are portions of terrain, defined by the general requirement of maximizing homogeneity within a single unit and heterogeneity between different ones. Slope units are being used to describe a variety of processes and to assess different natural hazards. An unambiguous and reproducible definition of slope units based on quantitative hydrologic and topographic criteria was previously provided by the r.slopeunits software to automatically draw slope unit polygons on a digital surface. The software contains an adaptive algorithm allowing for a flexible yet well-defined slope unit delineation, by means of an iterative procedure. It requires a digital elevation model and a few input parameters, whose values must be optimized in a sound way, by means of multiple software runs and a proper objective function. The code is designed to quickly produce results on large areas, and in this work we devised an optimization algorithm to delineate slope units over the whole Italian peninsula. We outline the rationale of the optimization procedure for a general purpose slope unit delineation within very large areas. We present preliminary results in Central Italy, specifically a slope unit mosaic in the whole area affected by the 2016 earthquake sequence. The procedure represents a well-defined framework for slope unit delineation over the whole of Italy.

scholarly journals Nation-wide, general-purpose delineation of geomorphological slope units in Italy

2018 ◽  
Author(s):  
Massimiliano Alvioli ◽  
Ivan Marchesini ◽  
Fausto Guzzetti
Keyword(s):  
Adaptive Algorithm ◽  
Central Italy ◽  
Optimization Procedure ◽  
General Purpose ◽  
General Requirement ◽  
Italian Peninsula ◽  
Slope Unit ◽  
Digital Elevation ◽  
Elevation Model ◽  
Definition Of

Slope units are portions of terrain, defined by the general requirement of maximizing homogeneity within a single unit and heterogeneity between different ones. Slope units are being used to describe a variety of processes and to assess different natural hazards. An unambiguous and reproducible definition of slope units based on quantitative hydrologic and topographic criteria was previously provided by the r.slopeunits software to automatically draw slope unit polygons on a digital surface. The software contains an adaptive algorithm allowing for a flexible yet well-defined slope unit delineation, by means of an iterative procedure. It requires a digital elevation model and a few input parameters, whose values must be optimized in a sound way, by means of multiple software runs and a proper objective function. The code is designed to quickly produce results on large areas, and in this work we devised an optimization algorithm to delineate slope units over the whole Italian peninsula. We outline the rationale of the optimization procedure for a general purpose slope unit delineation within very large areas. We present preliminary results in Central Italy, specifically a slope unit mosaic in the whole area affected by the 2016 earthquake sequence. The procedure represents a well-defined framework for slope unit delineation over the whole of Italy.

scholarly journals Automatic delineation of geomorphological slope units with <tt>r.slopeunits v1.0</tt> and their optimization for landslide susceptibility modeling

2016 ◽  
Vol 9 (11) ◽  
pp. 3975-3991 ◽  
Author(s):  
Massimiliano Alvioli ◽  
Ivan Marchesini ◽  
Paola Reichenbach ◽  
Mauro Rossi ◽  
Francesca Ardizzone ◽  
...  
Keyword(s):  
Landslide Susceptibility ◽  
Central Italy ◽  
Optimization Approach ◽  
Optimal Parameters ◽  
Susceptibility Modeling ◽  
Digital Elevation ◽  
Terrain Units ◽  
Elevation Model ◽  
Reliable Software ◽  
Selection Of

Abstract. Automatic subdivision of landscapes into terrain units remains a challenge. Slope units are terrain units bounded by drainage and divide lines, but their use in hydrological and geomorphological studies is limited because of the lack of reliable software for their automatic delineation. We present the r.slopeunits software for the automatic delineation of slope units, given a digital elevation model and a few input parameters. We further propose an approach for the selection of optimal parameters controlling the terrain subdivision for landslide susceptibility modeling. We tested the software and the optimization approach in central Italy, where terrain, landslide, and geo-environmental information was available. The software was capable of capturing the variability of the landscape and partitioning the study area into slope units suited for landslide susceptibility modeling and zonation. We expect r.slopeunits to be used in different physiographical settings for the production of reliable and reproducible landslide susceptibility zonations.

scholarly journals Comparison of Different DEM Generation Methods based on Open Source Datasets

2019 ◽  
Vol 26 (1) ◽  
pp. 63-85
Author(s):  
Aya M. Hapep ◽  
Maythm AL-Bakri
Keyword(s):  
Open Source ◽  
Google Earth ◽  
Fundamental Information ◽  
Natural Neighbor ◽  
Open Source Data ◽  
Digital Elevation ◽  
Gis Data ◽  
South Of Iraq ◽  
Elevation Model ◽  
Definition Of

Digital Elevation Model (DEM) is one of the developed techniques for relief representation.  The definition of a DEM construction is the modeling technique of earth surface from existing data. DEM plays a role as one of the fundamental information requirement that has been generally utilized in GIS data structures. The main aim of this research is to present a methodology for assessing DEMs generation methods. The DEMs data will be extracted from open source data e.g. Google Earth. The tested data will be compared with data produced from formal institutions such as General Directorate of Surveying. The study area has been chosen in south of Iraq (Al-Gharraf / Dhi Qar governorate. The methods of DEMs creation are kriging, IDW (inverse distance weight), spline, and natural neighbor. This research used different software for processing and analysis such as ArcGIS 10.2, TCX and Civil 3D. Two- sample t-test has been adopted to investigate the mean of elevation differences between compared datasets. The results showed that the spline is the best method that can be used to build DEM in this study area.

"Terra Antiqua" : a paleogeographic reconstruction plugin for QGIS

2020 ◽  
Author(s):  
Diego Ruiz ◽  
Guillaume Dupont-Nivet ◽  
Jovid Aminov ◽  
Fernando Poblete ◽  
Thomas van der Linden ◽  
...  
Keyword(s):  
Environmental Science ◽  
Industrial Applications ◽  
Large Set ◽  
Sequential Procedures ◽  
Digital Elevation ◽  
Geologic Maps ◽  
Elevation Model ◽  
Definition Of ◽  
Project Data ◽  
User Friendly

&lt;p&gt;Paleogeographic reconstructions are essential across disciplines in Earth and Environmental Science from geodynamics to climate, as well as related fields of biology and ecology. They are at the foundation of many academic as well as industrial applications. As for geologic maps, paleogeographic reconstructions integrate a vast amount of multidisciplinary data and interpretations. Building such reconstructions thus requires a large set of sequential procedures to position around the globe various oceanic and continental features and to modify their topographies, bathymetries and shorelines according to the considered dataset included.&lt;/p&gt;&lt;p&gt;We present here a tool that enables to perform simply these operations. It is under development as a plugin for QGIS. With a graphical user interface, preset options can be readily applied to generate quickly multiple reconstructions with varying parameters. This makes project data management and treatment considerably easier, more intuitive and user-friendly. As most tools in GIS do, Terra Antiqua includes help texts incorporated to its interface to guide the user through each module.&amp;#160; The Plugin is divided into modules and this format allows a high degree of flexibility in the order of the reconstruction steps. These are: the compilation of topography and bathymetry, the definition of the paleoshorelines, the topography modification and the interpolation. Resulting paleogeography digital elevation model (DEM) can be visualized and exported in any GIS-supported format &amp;#8211; NetCDF, GeoTIFF, Grid (.grd) or as PDF, JPEG, SVG etc. for publication. The tool is tested to make global reconstructions at 50 and 30 Ma.&lt;/p&gt;

scholarly journals Automatic Mapping and Characterisation of Linear Depositional Bedforms: Theory and Application Using Bathymetry from the North West Shelf of Australia

2022 ◽  
Vol 14 (2) ◽  
pp. 280
Author(s):  
Ulysse Lebrec ◽  
Rosine Riera ◽  
Victorien Paumard ◽  
Michael J. O'Leary ◽  
Simon C. Lang
Keyword(s):  
North West ◽  
The North ◽  
Digital Elevation ◽  
Automated Measurements ◽  
Automatic Mapping ◽  
Neighbourhood Analysis ◽  
Study Support ◽  
Elevation Model ◽  
Definition Of ◽  
Automated Methods

Bedforms are key components of Earth surfaces and yet their evaluation typically relies on manual measurements that are challenging to reproduce. Several methods exist to automate their identification and calculate their metrics, but they often exhibit limitations where applied at large scales. This paper presents an innovative workflow for identifying and measuring individual depositional bedforms. The workflow relies on the identification of local minima and maxima that are grouped by neighbourhood analysis and calibrated using curvature. The method was trialed using a synthetic digital elevation model and two bathymetry surveys from Australia’s northwest marine region, resulting in the identification of nearly 2000 bedforms. The comparison of the metrics calculated for each individual feature with manual measurements show differences of less than 10%, indicating the robustness of the workflow. The cross-comparison of the metrics resulted in the definition of several sub-types of bedforms, including sandwaves and palaeoshorelines, that were then correlated with oceanic conditions, further corroborating the validity of the workflow. Results from this study support the idea that the use of automated methods to characterise bedforms should be further developed and that the integration of automated measurements at large scales will support the development of new classification charts that currently rely solely on manual measurements.

scholarly journals Pannonian plain as a morphostructural unit of Serbia

2012 ◽  
Vol 92 (1) ◽  
pp. 47-70 ◽  
Author(s):  
Jelena Calic ◽  
Marko Milosevic ◽  
Tivadar Gaudenji ◽  
Dragoljub Strbac ◽  
Milovan Milivojevic
Keyword(s):  
Pannonian Basin ◽  
Geological Structure ◽  
Roughness Coefficient ◽  
Digital Elevation ◽  
Pannonian Plain ◽  
The Status ◽  
The Republic ◽  
Elevation Model ◽  
Definition Of ◽  
Basin System

Differentiation between the terms ?Pannonian Basin? and ?Pannonian Plain? is not clear enough in geographical literature. The paper discusses the usage of the term ?plain? in geomorphology, as well as the usage of a quantitative method for plain delineation, through calculation of relief roughness coefficient (using a digital elevation model). Qualitative analysis, which includes the definition of dominant geomorphological processes and the distribution of Quaternary sediments, is an addition to the quantitative analysis. In the Republic of Serbia, the area of the Pannonian plain defined in this way is 24,448 km2, which is 27.5% of the total territory of the country. The paper gives the overview of the geotectonic structure and evolution of the Pannonian Basin System, with special stress on the territory of Serbia, as well as the chronology of the Pannonian sedimentation area in Serbia from the Lower Miocene till present. In order to explain the status of the Pannonian plain as one of the morphostructural units of Serbia, the theoretical basics of morphostructures are discussed, as well as the principles of their spatial definition and the relation to the notion of a geological structure.

scholarly journals A SINGLE-PASS AIRBORNE INTERFEROMETRIC CALIBRATION METHOD RESEARCH FOR DEM MAPPING

2020 ◽  
Vol XLIII-B1-2020 ◽  
pp. 331-336
Author(s):  
L. J. Lu ◽  
G. M. Huang
Keyword(s):  
Geometric Model ◽  
Three Dimensional ◽  
Optimization Procedure ◽  
Real Data ◽  
Calibration Method ◽  
Baseline Length ◽  
Three Dimensional Model ◽  
Single Pass ◽  
Digital Elevation ◽  
Elevation Model

Abstract. This paper presents a novel single-pass airborne interferometric calibration method with a limited Number GCPs for InSAR digital elevation model (DEM) mapping. The proposed method is based on a rigorous three-dimensional model for a single-pass airborne InSAR system. The corrected InSAR parameters of baseline length, baseline inclination, near slant range, and Doppler centroid frequency, as well as phase offset, can be jointly solved via a unified optimization procedure in terms of the constructed three-dimensional geometric model using a limited number ground control points (GCPs). The proposed method is evaluated on real data of the CASMSAR system in X-band, the final DEMs generated by the calibration processing achieve a high accuracy level (1–3 m standard deviation), even in the presence of only 3–5 GCPs.

scholarly journals The use of FLO2D numerical code in lahar hazard evaluation at Popocatépetl volcano: a 2001 lahar scenario

2014 ◽  
Vol 14 (12) ◽  
pp. 3345-3355 ◽  
Author(s):  
L. Caballero ◽  
L. Capra
Keyword(s):  
Rheological Properties ◽  
Numerical Code ◽  
Hazard Evaluation ◽  
Digital Elevation ◽  
Popocatépetl Volcano ◽  
Elevation Model ◽  
Definition Of ◽  
Digital Elevation Model Resolution ◽  
Excellent Tool ◽  
Popocatepetl Volcano

Abstract. Lahar modeling represents an excellent tool for designing hazard maps. It allows the definition of potential inundation zones for different lahar magnitude scenarios and sediment concentrations. Here, we present the results obtained for the 2001 syneruptive lahar at Popocatépetl volcano, based on simulations performed with FLO2D software. An accurate delineation of this event is needed, since it is one of the possible scenarios considered if magmatic activity increases its magnitude. One of the main issues for lahar simulation using FLO2D is the calibration of the input hydrograph and rheological flow properties. Here, we verified that geophone data can be properly calibrated by means of peak discharge calculations obtained by the superelevation method. Digital elevation model resolution also resulted as an important factor in defining the reliability of the simulated flows. Simulation results clearly show the influence of sediment concentrations and rheological properties on lahar depth and distribution. Modifying rheological properties during lahar simulation strongly affects lahar distribution. More viscous lahars have a more restricted aerial distribution and thicker depths, and resulting velocities are noticeably smaller. FLO2D proved to be a very successful tool for delimitating lahar inundation zones as well as generating different lahar scenarios not only related to lahar volume or magnitude, but also taking into account different sediment concentrations and rheologies widely documented as influencing lahar-prone areas.

scholarly journals A New Beach Topography-Based Method for Shoreline Identification

Water ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3110
Author(s):  
Marco Luppichini ◽  
Monica Bini ◽  
Marco Paterni ◽  
Andrea Berton ◽  
Silvia Merlino
Keyword(s):  
High Resolution ◽  
Digital Elevation Model ◽  
Structure From Motion ◽  
Sea Water ◽  
Beach Profile ◽  
Digital Elevation ◽  
Profile Changes ◽  
Elevation Model ◽  
Definition Of ◽  
Reflecting Surfaces

The definition of shoreline is not the same for all contexts, and it is often a subjective matter. Various methods exist that are based on the use of different instruments that can determine and highlight a shoreline. In recent years, numerous studies have employed photogrammetric methods, based on different colours, to map the boundary between water and land. These works use images acquired by satellites, drones, or cameras, and differ mainly in terms of resolution. Such methods can identify a shoreline by means of automatic, semi-automatic, or manual procedures. The aim of this work is to find and promote a new and valid beach topography-based algorithm, able to identify the shoreline. We apply the Structure from Motion (SfM) techniques to reconstruct a high-resolution Digital Elevation Model by means of a drone for image acquisition. The algorithm is based on the variation of the topographic beach profile caused by the transition from water to sand. The SfM technique is not efficient when applied to reflecting surfaces like sea water resulting in a very irregular and unnatural profile over the sea. Taking advantage of this fact, the algorithm searches for the point in the space where a beach profile changes from irregular to regular, causing a transition from water to land. The algorithm is promoted by the release of a QGIS v3.x plugin, which allows the easy application and extraction of other shorelines.

scholarly journals Spatial and temporal analysis of the snow line in the alps : based on NOAA-AVHRR data

2002 ◽  
Vol 57 (3) ◽  
pp. 170-183 ◽  
Author(s):  
S. Wunderle ◽  
M. Droz ◽  
H. Kleindienst
Keyword(s):  
Satellite Data ◽  
Temporal Analysis ◽  
High Temporal Resolution ◽  
Noaa Avhrr ◽  
Snow Line ◽  
Digital Elevation ◽  
Avhrr Data ◽  
Elevation Model ◽  
Definition Of ◽  
The Impact

Abstract. A method to derive the snow line elevation using NOAA-AVHRR satellite data in combination with a digital elevation model is presented. The AVHRR sensor enables the frequent Observation of snow cover with a sufficiently high temporal resolution. The definition of the snow line and the impact of geocoding errors, as well as errors due to misclassification, are discussed. A comparison of the NOAA-AVHRR data with data from the higher resolution IRS-WiFS indicates that even at a spatial resolution of 1.1 km, a quantitative analysis of the snow line elevation is possible. The influence of different winter conditions in Switzerland on the elevation of the snow line is reflected in satellite data from 1990,1996 and 1999. The results of the investigation were, firstly the presentation of the spatial pattern of the average snow line elevation, secondly the derivation of snow line signatures for three regions. These were then compared with the Overall alpine snow line signature.

Sign in / Sign up

Export Citation Format

Share Document