Automatic Extraction of Intermittent Channel Systems of a Low‐Relief, Low‐Gradient Floodplain

2021 ◽  
Author(s):  
Haiqing Xu ◽  
Shailesh van der Steeg ◽  
Raymond Torres
Keyword(s):  
Mathematical Morphology ◽  
Channel Length ◽  
Reference Network ◽  
Automatic Extraction ◽  
River Floodplain ◽  
Flow Accumulation ◽  
The Past ◽  
Digital Elevation ◽  
Reference Map ◽  
Channel Systems

<p>Intermittent floodplain channels are low‐relief conduits etched into the floodplain surface and remain dry much of the year. These channels comprise expansive systems and are important because during low‐level inundation they facilitate lateral hydraulic connectivity throughout the floodplain. Nevertheless, few studies have focused on these floodplain channels due to uncertainty in how to identify and characterize these systems in digital elevation models (DEMs). In particular, their automatic extraction from widely available DEMs is challenging due to the characteristically low‐relief and low‐gradient topography of floodplains. We applied three channel extraction approaches to the Congaree River floodplain DEM and compared the results to a channel reference map created through numerous field excursions over the past 30 years. The methods that we tested are based on flow accumulation area, topographic curvature, and mathematical morphology, or the D8, Laplacian, and bottom‐hat transform (BHT), respectively. Of the 198 km of reference channels the BHT, Laplacian, and D8 extracted 83%, 71%, and 23%, respectively, and the BHT consistently had the highest agreement with the reference network at the local (5 m) and regional (10 km) scales. The extraction results also include commission “error”, augmenting the reference map with about 100 km of channel length. Overall, the BHT method provided the best results for channel extraction, giving over 298 km in 69 km2 with a detrended regional relief of 1.9 m.</p>

Verifying calculated flow accumulation patterns of mapped and unmapped forest streams by culvert location

2007 ◽  
Vol 83 (2) ◽  
pp. 198-206 ◽  
Author(s):  
Paul N.C. Murphy ◽  
Jae Ogilvie ◽  
Mark Castonguay ◽  
Fan-Rui Meng ◽  
Paul A Arp
Keyword(s):  
Digital Elevation Model ◽  
Predictive Ability ◽  
Channel Length ◽  
Water Drainage ◽  
Forest Operations ◽  
Operations Planning ◽  
Flow Accumulation ◽  
Additional Information ◽  
Digital Elevation ◽  
Elevation Model

Access to reliable surface water drainage information is important to forest operations planning in road layout and construction, culvert location and size, cutblock and harvest trail layout, site preparation and regeneration, and off-road navigation. A GIS-based process leading to an improved map of surface drainage is described and tested for the University of New Brunswick forest. This process predicts flow accumulation by combining the predictive ability of a digital elevation model (DEM) with additional information provided by mapped hydrographic features. Previously unmapped flow channels were reliably mapped with this process; 88% of predicted culvert locations were within 40 m of the actual location. Total channel length mapped increased 11.7 times over the existing maps. Key words: digital elevation model, forest operations planning, surface hydrology, flow accumulation

scholarly journals MAT: GIS-Based Morphometry Assessment Tools for Concave Landforms

2021 ◽  
Vol 13 (14) ◽  
pp. 2810
Author(s):  
Joanna Gudowicz ◽  
Renata Paluszkiewicz
Keyword(s):  
Rapid Development ◽  
Assessment Tools ◽  
Lidar Data ◽  
Automatic Extraction ◽  
Sensing Technology ◽  
Digital Elevation ◽  
Elevation Data ◽  
Elevation Model ◽  
Morphometric Assessment ◽  
Morphometric Evaluation

The rapid development of remote sensing technology for obtaining high-resolution digital elevation models (DEMs) in recent years has made them more and more widely available and has allowed them to be used for morphometric assessment of concave landforms, such as valleys, gullies, glacial cirques, sinkholes, craters, and others. The aim of this study was to develop a geographic information systems (GIS) toolbox for the automatic extraction of 26 morphometric characteristics, which include the geometry, hypsometry, and volume of concave landforms. The Morphometry Assessment Tools (MAT) toolbox in the ArcGIS software was developed. The required input data are a digital elevation model and the form boundary as a vector layer. The method was successfully tested on an example of 21 erosion-denudation valleys located in the young glacial area of northwest Poland. Calculations were based on elevation data collected in the field and LiDAR data. The results obtained with the tool showed differences in the assessment of the volume parameter at the average level of 12%, when comparing the field data and LiDAR data. The algorithm can also be applied to other types of concave forms, as well as being based on other DEM data sources, which makes it a universal tool for morphometric evaluation.

scholarly journals Setting the Flow Accumulation Threshold Based on Environmental and Morphologic Features to Extract River Networks from Digital Elevation Models

2021 ◽  
Vol 10 (3) ◽  
pp. 186
Author(s):  
HuiHui Zhang ◽  
Hugo A. Loáiciga ◽  
LuWei Feng ◽  
Jing He ◽  
QingYun Du
Keyword(s):  
Spatial Scales ◽  
Digital Elevation Models ◽  
Regional Scale ◽  
Drainage Density ◽  
River Network ◽  
Landscape Patterns ◽  
Estimation Methods ◽  
River Networks ◽  
Flow Accumulation ◽  
Digital Elevation

Determining the flow accumulation threshold (FAT) is a key task in the extraction of river networks from digital elevation models (DEMs). Several methods have been developed to extract river networks from Digital Elevation Models. However, few studies have considered the geomorphologic complexity in the FAT estimation and river network extraction. Recent studies estimated influencing factors’ impacts on the river length or drainage density without considering anthropogenic impacts and landscape patterns. This study contributes two FAT estimation methods. The first method explores the statistical association between FAT and 47 tentative explanatory factors. Specifically, multi-source data, including meteorologic, vegetation, anthropogenic, landscape, lithology, and topologic characteristics are incorporated into a drainage density-FAT model in basins with complex topographic and environmental characteristics. Non-negative matrix factorization (NMF) was employed to evaluate the factors’ predictive performance. The second method exploits fractal geometry theory to estimate the FAT at the regional scale, that is, in basins whose large areal extent precludes the use of basin-wide representative regression predictors. This paper’s methodology is applied to data acquired for Hubei and Qinghai Provinces, China, from 2001 through 2018 and systematically tested with visual and statistical criteria. Our results reveal key local features useful for river network extraction within the context of complex geomorphologic characteristics at relatively small spatial scales and establish the importance of properly choosing explanatory geomorphologic characteristics in river network extraction. The multifractal method exhibits more accurate extracting results than the box-counting method at the regional scale.

scholarly journals Influência de lineamentos estruturais no desencadeamento dos movimentos de massa no maciço de Uruburetama, Ceará

2020 ◽  
Vol 13 (3) ◽  
pp. 1294
Author(s):  
Eduardo Viana Freires ◽  
Cláudio Ângelo da Silva Neto ◽  
Cynthia Romariz Duarte ◽  
César Ulisses Vieira Veríssimo ◽  
Daniel Dantas Moreira Gomes ◽  
...  
Keyword(s):  
High Energy ◽  
Automatic Extraction ◽  
Mass Movements ◽  
Alos Palsar ◽  
Geological Structures ◽  
Physical Conditions ◽  
Directional Filters ◽  
Digital Elevation ◽  
Predominant Orientation ◽  
Elevation Model

A disposição de estruturas geológicas em áreas planálticas é elemento importante na compreensão da dinâmica que ocorre na superfície de suas encostas e que é responsável pela esculturação do relevo. Neste contexto destacam-se os movimentos gravitacionais, que podem gerar perdas econômicas, ambientais e humanas em eventos de alta energia e/ou com grande extensão. Esta pesquisa analisou a influência de lineamentos estruturais no desencadeamento dos movimentos gravitacionais no maciço de Uruburetama, localizado no estado do Ceará. A metodologia consistiu na extração automática de lineamentos a partir do Modelo Digital de Elevação (MDE) fornecido pelo sensor orbital ALOS PALSAR. A partir da média de filtros direcionais aplicados a 0°, 45°, 90° e 135° de iluminação foi possível realçar as feições lineares da imagem original, facilitando sua extração. Posteriormente, foram elaborados mapas de distribuição espacial e densidade de lineamentos, além de diagrama de roseta. Tais produtos subsidiaram a análise da disposição dos principais trends estruturais da área, destacando que a maior densidade e a orientação predominante de lineamentos podem ser indicativas do grau de susceptibilidade à ocorrência de movimentos de massa no maciço de Uruburetama, desde que também sejam consideradas as características físicas dominantes e o grau de intervenção humana nas encostas. Os resultados demonstraram que os lineamentos estruturais obtidos de forma automática, quando analisados em conjunto com as características ambientais podem ser aplicados na análise de susceptibilidade à ocorrência de movimentos de massa.  Influence of structural lineaments as a trigger of mass movements in the Uruburetama massif, Ceará state, Brazil A B S T R A C TThe geological structures arrangement in plateau areas is an important element in understanding the dynamics that occur on the surface of their slopes and which is responsible for relief sculpting. In this context, gravitational movements stand out, which can generate economic, environmental and human losses in high energy events and / or with large extension. This research analyzed the influence of structural lineaments in the gravitational movements triggering in the Uruburetama massif, located in the state of Ceará. The methodology consisted of automatic extraction of lineaments from the Digital Elevation Model (DEM) provided by the ALOS PALSAR orbital sensor. From the average of directional filters applied at 0°, 45°, 90° and 135° of illumination it was possible to enhance the linear features of the original image, facilitating their extraction. Subsequently, maps of spatial distribution and lineaments density were developed, as well as a rosette diagram. Such products subsidized the analysis of the disposition of the main structural trends of the area, emphasizing that the higher density and the predominant orientation of lineaments may be indicative of the degree of susceptibility to the occurrence of mass movements in the Uruburetama massif, if the dominant physical conditions and the degree of human intervention on the slopes are also considered. The results showed that the structural lineaments obtained automatically, when analyzed together with the environmental characteristics can be applied in the susceptibility analysis to the occurrence of mass movements.Keywords: ALOS PALSAR, directional filters, image fusion, lineaments extraction

scholarly journals The Effect of Doping on Different FET Structures: MOSFET, TFET and FinFET

2020 ◽  
Vol 9 (6) ◽  
pp. 972-979
Keyword(s):  
Drain Current ◽  
Channel Length ◽  
Short Channel Effects ◽  
Poor Control ◽  
Short Channel ◽  
Circuit Performance ◽  
The Past ◽  
Channel Effects ◽  
Circuit Density ◽  
Effect Of Doping

MOSFET have been scaled down over the past few years in order to give rise to high circuit density and increase the speed of circuit. But scaling of MOSFET leads to issues such as poor control gate over the current which depends on gate voltage. Many short channel effects (SCE) influence the circuit performance and leads to the indeterminist response of drain current. These effects can be decreased by gate excitation or by using multiple gates and by offering better control gate the device parameters. In Single gate MOSFET, gate electric field decreases but multigate MOSFET or FinFET provides better control over drain current. In this paper, different FET structures such as MOSFET, TFET and FINFET are designed at 22nm channel length and effect of doping had been evaluated and studied. To evaluate the performance donor concentration is kept constant and acceptor concentration is varied.

scholarly journals Retrieval of similar topographic areas.

2016 ◽  
Vol 47 (1) ◽  
pp. 275
Author(s):  
E. Kokinou ◽  
C. Panagiotakis ◽  
Th. Kinigopoulos
Keyword(s):  
Image Processing ◽  
High Efficiency ◽  
Automatic Extraction ◽  
Local Minima ◽  
Initial Model ◽  
Area Of Interest ◽  
Digital Elevation ◽  
Elevation Data ◽  
Digital Elevation Data ◽  
Step Number

Image processing and understanding and further pattern recognition comprises a precious tool for the automatic extraction of information using digital topography. The aim of this work is the retrieval of areas with similar topography using digital elevation data. It can be applied to geomorphology, forestry, regional and urban planning, and many other applications for analyzing and managing natural resources. In specifics, the user selects the area of interest, navigating overhead a high resolution elevation image and determines two (3) parameters (step, number of local minima and display scale). Furthermore the regions with similar relief to the initial model are determined. Experimental results show high efficiency of the proposed scheme.

scholarly journals Strengths of Exaggerated Tsunami-Originated Placenames: Disaster Subculture in Sanriku Coast, Japan

2019 ◽  
Vol 8 (10) ◽  
pp. 429 ◽  
Author(s):  
Yuzuru Isoda ◽  
Akio Muranaka ◽  
Go Tanibata ◽  
Kazumasa Hanaoka ◽  
Junzo Ohmura ◽  
...  
Keyword(s):  
Low Frequency ◽  
Local Area ◽  
Local Communities ◽  
Sanriku Coast ◽  
The Past ◽  
Disaster Experience ◽  
Digital Elevation ◽  
Disaster Subculture ◽  
Group Interviews ◽  
Elevation Model

Disaster-originated placename is a kind of disaster subculture that is used for a practical purpose of identifying a location while reminding the past disaster experience. They are expected to transmit the risks and knowledge of high-risk low-frequency natural hazards, surviving over time and generations. This paper compares the perceptions to tsunami-originated placenames in local communities having realistic and exaggerated origins in Sanriku Coast, Japan. The reality of tsunami-originated placenames is first assessed by comparing the tsunami run-ups indicated in the origins and that of the tsunami in the Great East Japan Earthquake 2011 using GIS and digital elevation model. Considerable proportions of placenames had exaggerated origins, but the group interviews to local communities revealed that origins indicating unrealistic tsunami run-ups were more believed than that of the more realistic ones. We discuss that accurate hazard information will be discredited if it contradicts to the people’s everyday life and the desire for safety, and even imprecise and ambiguous information can survive if it is embedded to a system of local knowledge that consistently explains the various facts in a local area that requires explanation.

25 years of movement monitoring on South Peak, Turtle Mountain: understanding the hazard

2009 ◽  
Vol 46 (3) ◽  
pp. 256-269 ◽  
Author(s):  
Corey R. Froese ◽  
Francisco Moreno ◽  
Michel Jaboyedoff ◽  
David M. Cruden
Keyword(s):  
Monitoring Program ◽  
Rock Avalanche ◽  
Light Detection And Ranging ◽  
Short Term ◽  
The Past ◽  
Digital Elevation ◽  
Government Project ◽  
Elevation Model ◽  
Movement Monitoring ◽  
Deep Fractures

In 1981, an Alberta Government project upgraded the monitoring of South Peak, Turtle Mountain, on the south margin of the 1903 Frank Slide. The monitoring program aimed at understanding the rates of deformation over large, deep fractures encompassing South Peak and predicting a second large rock avalanche on the mountain. The monitoring program consisted of a complement of static ground points and remotely monitored targets measured periodically, and climatic, microseismic, and deformation data collected automatically on daily intervals and archived. In the late 1980s, developmental funding for the monitoring program ceased and some of the installations fell into disrepair. Between May 2004 and September 2006, readings from the remaining functional monitoring points were compiled and interpreted. In addition, readings compiled previously were re-interpreted based on a more recent understanding of short-term movement patterns and climatic influences. These observations were compared with recent observations from an airborne light detection and ranging (LiDAR) digital elevation model and field photographs to give more precise estimates of the overall rates, extent, and patterns of motion for the past 25 years.

Automatic Extraction of Valency Information

1995 ◽  
Vol 107-108 ◽  
pp. 89-111
Author(s):  
Jan Daugaard ◽  
Sabine Kirchmeier-Andersen ◽  
Lene Schøsler
Keyword(s):  
Natural Language ◽  
Research Team ◽  
Corpus Analysis ◽  
Automatic Extraction ◽  
The Past ◽  
Natural Language Parsing ◽  
Theoretical Assumptions ◽  
The Creation

Abstract The above research team has for the past 4 years been working on a database of valency schemes for 4,000 Danish verbs. First we present the underlying theoretical assumptions for the creation of valency schemes. Then the tools to perform automatic extraction of valency information from corpora are described. Finally, the results are presented. Keywords: natural language parsing, Danish, lexical valency, the Pronominal Approach, corpus analysis.

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