RPAS-SfM 4D mapping of shallow landslides activated in a steep terraced vineyard

2021 ◽  
Author(s):  
Luca Mauri ◽  
Eugenio Straffelini ◽  
Sara Cucchiaro ◽  
Paolo Tarolli
Keyword(s):  
High Resolution ◽  
Low Cost ◽  
Features Extraction ◽  
Shallow Landslides ◽  
Agricultural System ◽  
Agricultural Systems ◽  
The Road ◽  
Starting Point ◽  
Multi Temporal ◽  
Geomorphological Changes

<p>The presence of roads is closely linked with the activation of land degradative phenomena such as landslides. Factors such as ineffective road management and design, local rainfall regimes and specific geomorphological elements actively influence landslides occurrence. In this context, recent developments in digital photogrammetry (e.g. Structure from Motion; SfM) paired with Remotely Piloted Aircraft Systems (RPAS) increase our possibilities to realize low-cost and recurrent topographic surveys. This allows the realization of multi-temporal (hereafter 4D) and high-resolution Digital Elevation Models (DEMs), fundamental to analyse geomorphological features and quantify processes at the fine spatial and temporal resolutions at which they occur. In this research is presented a 4D comparison of geomorphological indicators describing a landslide-prone agricultural system, so as to detect the noticed high-steep slope failures. The possibility to analyse the evolution of landslide geomorphic features in steep agricultural systems through high-resolution and 4D comparison of such indicators is still a challenge to be investigated. In this research, we considered a case study located in the central Italian Alps, where two shallow landslides (L1, L2) were activated below a rural road within a terraced vineyard. The dynamics of the landslides were monitored through the comparison of repeated DEMs (DEM of Difference, i.e. DoD), that reported erosion values of above 20 m<sup>3</sup> and 10 m<sup>3</sup> for the two landslides zones and deposition values of more than 15 m<sup>3</sup> and 9 m<sup>3</sup> respectively. The elaboration of Relative Path Impact Index (RPII) highlighted the role played by the road in the alteration of surface water flow directions. Altered water flows were expressed by values between 2σ and 4σ of RPII close to the collapsed surfaces. The increasing of profile curvature and roughness index described landslides evolution over time. Finally, the multi-temporal comparison of features extraction underlined the geomorphological changes affecting the study area. The computation of the quality index underlined the accuracy of features extraction. This index is expressed in a range between 0 (low accuracy) and 1 (high accuracy) and resulted equal to 0.22 m, regarding the landslide observed during the first RPAS survey (L1-pre); 0.63 m, concerning the same landslide detected during the second RPAS survey (L1-post); 0.69 m for L2. Results prove the usefulness of high-resolution and 4D RPAS-based SfM surveys for the investigation of landslides triggering due to the presence of roads at hillslope scale in agricultural systems. This work could be a useful starting point for further studies of landslide-susceptible zones at a wider scale, to preserve the quality and the productivity of affected agricultural areas.</p>

scholarly journals UAV-SfM 4D mapping of landslides activated in a steep terraced agricultural area

2021 ◽  
Vol 52 (1) ◽  
Author(s):  
Luca Mauri ◽  
Eugenio Straffelini ◽  
Sara Cucchiaro ◽  
Paolo Tarolli
Keyword(s):  
High Resolution ◽  
Low Cost ◽  
Agricultural System ◽  
Agricultural Systems ◽  
Temporal Comparison ◽  
Landslide Occurrence ◽  
Water Flows ◽  
Starting Point ◽  
Multi Temporal ◽  
Geomorphological Changes

The presence of roads is closely linked with the activation of land degradative phenomena such as landslides. Factors such as ineffective road management and design, local rainfall regimes, and specific geomorphological elements actively influence landslide occurrence. In this context, recent developments in digital photogrammetry (e.g., Structure from Motion; SfM) paired with Uncrewed Aerial Vehicles (UAV) systems increase our possibilities to realize low-cost and recurrent topographic surveys. This can lead to the development of multi-temporal (hereafter: 4D) and high-resolution Digital Elevation Models (DEMs), which are fundamental to analyse geomorphological features and quantify processes at the fine spatial and temporal resolutions at which they occur. This research proposes a multi-temporal comparison of the main geomorphometric indicators describing a landslide-prone terraced vineyard to assess the observed high-steep slope failures. The possibility to investigate the evolution of landslide geomorphic features in steep agricultural systems through a high-resolution and 4D comparison of such indicators is still a challenge to be explored. In this article, we considered a case study located in the central Italian Alps, where two landslides were activated below a rural road within a terraced agricultural system. The dynamics of the landslides were monitored by comparing repeated DEMs (DEM of difference), which reported erosion values of above 20 m3 and 10 m3 for the two landslide zones and deposition values of more than 15 m3 and 9 m3, respectively. The road network’s role in the alteration of superficial water flows was proved by the elaboration of the relative path impact index. Altered water flows were expressed by values between 2σ and 4σ close to the collapsed surfaces. The increase in profile curvature and roughness index described the landslides evolution over time. Finally, the multi-temporal comparison of feature extraction underlined the geomorphological changes affecting the study area. The accuracy of features extraction was analysed through the quality index computation, expressed in a range between 0 (low accuracy) and 1 (high accuracy), and proved to be equal to 0.22 m (L1-pre), 0.63 m (L1-post), and 0.69 m (L2). Results confirmed the usefulness of high-resolution and 4D UAV-based SfM surveys to investigate landslides triggering due to the presence of roads at hillslope scale in agricultural systems. This work could be a useful starting point for further studies of landslide- susceptible zones on a wider scale to preserve the quality and the productivity of affected agricultural areas.

Modelling of overland flows in a terraced vineyard affected by road-induced shallow landslides 

2021 ◽  
Author(s):  
Luca Mauri ◽  
Eugenio Straffelini ◽  
Paolo Tarolli
Keyword(s):  
Water Flow ◽  
Land Degradation ◽  
Shallow Landslides ◽  
Agricultural System ◽  
Drainage Systems ◽  
The Road ◽  
Water Flows ◽  
Erosion Processes ◽  
Starting Point ◽  
Multi Temporal

<p>Land degradation represents one the main issue affecting agricultural systems, especially in those areas that are characterized by agricultural practices on steep hillslopes. The occurrence of erosion processes and landslides is closely linked with the presence of road networks. Factors like inefficient of absent drainage systems, wasteful road management and not optimal planning, as well as specific geomorphological and hydrological elements directly encourage landslides activation. In this connection, the combined use of Remotely Piloted Aircraft Systems (RPAS) and photogrammetric techniques (e.g. Structure from Motion; SfM) allowed to elaborate multi-temporal (therefore 4D) high-resolution Digital Elevation Models (DEMs), so as to detect geomorphological changes affecting earth surface at specific spatial and temporal scale. At the same time, the adoption of several models allows to compute specific hydrological analysis, for instance investigating the alteration of surface water flow dynamics due to the presence of specific features like roads. In this context, this research aims to propose a multi-temporal analysis of the road-induced water flow alterations in a shallow landslide-prone agricultural system. SIMWE model (Mitasova et al., 2013) was applied focusing on different geomorphic and rainfall scenarios, looking at the presence of the road network within the study area and assuming its absence through specific DEM post-processing procedures. In this connection, the possibility to perform multi-temporal hydrological simulations at the hillslope scale, to analyse the role played by the road in landslides activation is still a challenge to be investigated. In this article, we considered a case study placed in northern Italy, where two shallow landslides were observed below a rural road located within a terraced vineyard. Multi-temporal hydrological simulations were conducted to further analyse the evolution of road induced water flows deviations, thus stimulating landslides occurrence on the detected hillslopes. Maximum water depths equal to 0.60 m and 0.46 m were noticed close to specific zones of the road sections located above the first and the second landslide respectively. The simulations computed assuming the absence of the road revealed the lack of water flows deviations involving the landslide zones, underlining the fact that the road absence would avoid significant changes in water flow paths toward the collapsed zones. The key role played by the road in water flows deviation and in the evolution of the observed land degradation dynamics was attested through the comparison of the thematic maps resulted from each simulation. This work could be a solid starting point for further analyse the roads impact on runoff dynamics at a wider scale, aiming to plan and propose mitigation interventions so as to reduce the occurrence of future risk scenarios. At the same time, efficient design of drainage systems along the roadway could be conducted starting from the outcomes presented in our research, so as to prevent the activation of similar land degradation processes.</p><p><br><strong>Reference<br></strong>Mitasova H., Barton C.M., Ullah I., Hofierka J., Harmon R.S. 2013. GIS-Based Soil Erosion Modeling. Treatise on Geomorphology (3), 228-258.</p>

scholarly journals GEOMORPHOLOGICAL MAPPING WITH TERRESTRIAL LASER SCANNING AND UAV-BASED IMAGING

2016 ◽  
Vol XLI-B5 ◽  
pp. 591-597 ◽  
Author(s):  
N. Tilly ◽  
D. Kelterbaum ◽  
R. Zeese
Keyword(s):  
High Resolution ◽  
Laser Scanning ◽  
Low Cost ◽  
Terrestrial Laser Scanning ◽  
Small Scale ◽  
Data Sets ◽  
Geomorphological Mapping ◽  
3D Data ◽  
Multi Temporal ◽  
Mean Differences

High-resolution digital elevation models (DEMs) are useful for the detailed mapping of geomorphological features. Nowadays various sensors and platforms are available to collect 3D data. The presented study compares terrestrial laser scanning (TLS) and low-cost unmanned aerial vehicles (UAV)-based imaging in terms of their usability for capturing small-scale surface structures. In October 2014 and June 2015 measurements with both systems were carried out in an episodically water-filled karst depression under pasture farming in the region of Hohenlohe (Southwest Germany). The overall aims were to establish high-resolution DEMs and monitor changes of the relief caused by dissolution and compare the advantages and drawbacks of both systems for such studies. Due to the short time between the campaigns the clear detection of temporal changes was hardly possible. However, the multi-temporal campaigns allowed an extensive investigation of the usability of both sensors under different environmental conditions. In addition to the remote sensing measurements, the coordinates of several positions in the study area were measured with a RTK-DGPS system as independent reference data sets in both campaigns. The TLS- and UAV-derived DEM heights at these positions were validated against the DGPS-derived heights. The accuracy of the TLS-derived values is supported by low mean differences between TLS and DGPS measurements while the UAV-derived models show a weaker performance. In the future years additional simultaneous measurements with both approaches under more similar vegetation conditions are necessary to detect surface movements. Moreover, by investigating the subsurface the interaction of above and below ground processes might be detected.

scholarly journals GEOMORPHOLOGICAL MAPPING WITH TERRESTRIAL LASER SCANNING AND UAV-BASED IMAGING

2016 ◽  
Vol XLI-B5 ◽  
pp. 591-597 ◽  
Author(s):  
N. Tilly ◽  
D. Kelterbaum ◽  
R. Zeese
Keyword(s):  
High Resolution ◽  
Laser Scanning ◽  
Low Cost ◽  
Terrestrial Laser Scanning ◽  
Small Scale ◽  
Data Sets ◽  
Geomorphological Mapping ◽  
3D Data ◽  
Multi Temporal ◽  
Mean Differences

High-resolution digital elevation models (DEMs) are useful for the detailed mapping of geomorphological features. Nowadays various sensors and platforms are available to collect 3D data. The presented study compares terrestrial laser scanning (TLS) and low-cost unmanned aerial vehicles (UAV)-based imaging in terms of their usability for capturing small-scale surface structures. In October 2014 and June 2015 measurements with both systems were carried out in an episodically water-filled karst depression under pasture farming in the region of Hohenlohe (Southwest Germany). The overall aims were to establish high-resolution DEMs and monitor changes of the relief caused by dissolution and compare the advantages and drawbacks of both systems for such studies. Due to the short time between the campaigns the clear detection of temporal changes was hardly possible. However, the multi-temporal campaigns allowed an extensive investigation of the usability of both sensors under different environmental conditions. In addition to the remote sensing measurements, the coordinates of several positions in the study area were measured with a RTK-DGPS system as independent reference data sets in both campaigns. The TLS- and UAV-derived DEM heights at these positions were validated against the DGPS-derived heights. The accuracy of the TLS-derived values is supported by low mean differences between TLS and DGPS measurements while the UAV-derived models show a weaker performance. In the future years additional simultaneous measurements with both approaches under more similar vegetation conditions are necessary to detect surface movements. Moreover, by investigating the subsurface the interaction of above and below ground processes might be detected.

The Road to the Baccalaureate

2020 ◽  
Vol 10 (2) ◽  
pp. 420-442
Author(s):  
Dina Ghazzawi ◽  
Lyle McKinney ◽  
Catherine Lynn Horn ◽  
Vincent Carales ◽  
Andrea Burridge
Keyword(s):  
Latin American ◽  
Academic Preparedness ◽  
African Students ◽  
Bachelor Degree ◽  
Caribbean Students ◽  
The Road ◽  
Community College District ◽  
Starting Point ◽  
Delayed Enrollment ◽  
Sub Saharan

International students are increasingly enrolling in U.S community colleges as a starting point to their higher education. However, limited research examines the factors contributing to their successful transfer to a 4-year institution and bachelor degree attainment. Utilizing longitudinal transcript data from a large community college district in Texas, this study uses hierarchical logistical regression to compare college experiences and transfer outcomes based on region of origin. Findings demonstrate that while Sub-Saharan African students have a significantly higher probability of transfer than Asian and Latin American students, the majority of bachelor degree recipients were Asian students graduating in STEM fields. Delayed enrollment into college and academic preparedness in math were negatively associated with transfer for Latin American and Caribbean students.

scholarly journals Evaluating the Safety Risk of Rural Roadsides Using a Bayesian Network Method

2019 ◽  
Vol 16 (7) ◽  
pp. 1166 ◽  
Author(s):  
Tianpei Tang ◽  
Senlai Zhu ◽  
Yuntao Guo ◽  
Xizhao Zhou ◽  
Yang Cao
Keyword(s):  
Bayesian Network ◽  
Low Cost ◽  
Road Networks ◽  
Access Point ◽  
Safety Risk ◽  
Crash Data ◽  
Risk Levels ◽  
The Road ◽  
Run Off ◽  
Point Density

Evaluating the safety risk of rural roadsides is critical for achieving reasonable allocation of a limited budget and avoiding excessive installation of safety facilities. To assess the safety risk of rural roadsides when the crash data are unavailable or missing, this study proposed a Bayesian Network (BN) method that uses the experts’ judgments on the conditional probability of different safety risk factors to evaluate the safety risk of rural roadsides. Eight factors were considered, including seven factors identified in the literature and a new factor named access point density. To validate the effectiveness of the proposed method, a case study was conducted using 19.42 km long road networks in the rural area of Nantong, China. By comparing the results of the proposed method and run-off-road (ROR) crash data from 2015–2016 in the study area, the road segments with higher safety risk levels identified by the proposed method were found to be statistically significantly correlated with higher crash severity based on the crash data. In addition, by comparing the respective results evaluated by eight factors and seven factors (a new factor removed), we also found that access point density significantly contributed to the safety risk of rural roadsides. These results show that the proposed method can be considered as a low-cost solution to evaluating the safety risk of rural roadsides with relatively high accuracy, especially for areas with large rural road networks and incomplete ROR crash data due to budget limitation, human errors, negligence, or inconsistent crash recordings.

scholarly journals Fabrication and Compressive Behavior of a Micro-Lattice Composite by High Resolution DLP Stereolithography

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 785
Author(s):  
Chow Shing Shin ◽  
Yu Chia Chang
Keyword(s):  
High Resolution ◽  
Lattice Structure ◽  
Low Cost ◽  
Hierarchical Structures ◽  
Dip Coating ◽  
Unit Cell ◽  
Digital Light Processing ◽  
Unit Cell Size ◽  
Wide Range ◽  
And Performance

Lattice structures are superior to stochastic foams in mechanical properties and are finding increasing applications. Their properties can be tailored in a wide range through adjusting the design and dimensions of the unit cell, changing the constituent materials as well as forming into hierarchical structures. In order to achieve more levels of hierarchy, the dimensions of the fundamental lattice have to be small enough. Although lattice size of several microns can be fabricated using the two-photon polymerization technique, sophisticated and costly equipment is required. To balance cost and performance, a low-cost high resolution micro-stereolithographic system has been developed in this work based on a commercial digital light processing (DLP) projector. Unit cell lengths as small as 100 μm have been successfully fabricated. Decreasing the unit cell size from 150 to 100 μm increased the compressive stiffness by 26%. Different pretreatments to facilitate the electroless plating of nickel on the lattice structure have been attempted. A pretreatment of dip coating in a graphene suspension is the most successful and increased the strength and stiffness by 5.3 and 3.6 times, respectively. Even a very light and incomplete nickel plating in the interior has increase the structural stiffness and strength by more than twofold.

scholarly journals The Productive Landscape in the Desert Margin for the Sustainable Development of Rural Settlements: An Innovative Greenbelt for Maranjab Desert in Iran

2021 ◽  
Vol 13 (4) ◽  
pp. 2077
Author(s):  
Mahnaz Sarlak ◽  
Laura Valeria Ferretti ◽  
Rita Biasi
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Low Cost ◽  
Agricultural Systems ◽  
Rural Settlements ◽  
Green Belt ◽  
The Sustainable Development ◽  
Research Questions ◽  
New Form ◽  
Low Levels

About two billion rural individuals depend on agricultural systems associated with a high amount of risk and low levels of yield in the drylands of Asia, Africa, and Latin America. Human activities, climate change and natural extreme events are the most important drivers of desertification. This phenomenon has occurred in many regions of Iran, particularly in the villages in the periphery of the central desert of Iran, and has made living in the oases so difficult that the number of abandoned villages is increasing every year. Land abandonment and land-use change increase the risk of desertification. This study aims to respond to the research questions: (i) does the planning of green infrastructures on the desert margin affect the distribution and balance of the population? (ii) how should the green belt be designed to have the greatest impact on counteracting desertification?, and (iii) does the design of productive landscape provide the solution? Through a wide-ranging and comprehensive approach, this study develops different scenarios for designing a new form of green belt in order to sustainably manage the issues of environmental protection, agricultural tradition preservation and desertification counteraction. This study proposes a new-traditional greenbelt including small low-cost and low-tech projects adapted to rural scale.

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