Characterizing the morphology of gully cross-sections based on PCA: A case of Yuanmou Dry-Hot Valley

Deng, Qi; Qin, Fanglu; Zhang, Bin; Wang, Haipeng; Luo, Mingliang; Chen, Shu; Liu, Hui; Liu, Gangcai

doi:10.1016/j.geomorph.2014.10.032

Cited by 82 publications

(65 citation statements)

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“…In addition, W B /W T and w/d gradually increased from the lower to the upper watershed, indicating that the gully shape was narrow, deep and V-shaped in the lower watershed and gradually became wider and shallower in the upper watershed, with a shallow, broad and U-shaped gully. The results were in good agreement with those from Deng et al (2015), which showed the percentage of U-shaped cross-sections were noticeably higher at the gully head than at other gully positions based on statistical methods. These results were also consistent with those from Chu (1956), in which gullies were classified based on the different cross-section shapes and development stages.…”

Section: Gully Cross-sectionsupporting

confidence: 85%

Gully morphological characteristics in the loess hilly‐gully region based on 3D laser scanning technique

Zheng

et al. 2018

Earth Surf Processes Landf

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Gully morphology characteristics can be used effectively to describe the status of gully development. The Chabagou watershed, located in the hilly‐gully region of the Loess Plateau in China, was selected to investigate gully morphological characteristics using a 3D laser scanning technique (LIDAR). Thirty‐one representative gullies located at different watershed locations and gully orders were chosen to quantitatively describe gully morphology and establish empirical equations for estimating gully volume based on gully length and gully surface area. Images and point cloud data for the 31 gullies were collected, and digital elevation models (DEMs) with 10‐cm resolution were generated. ArcGIS 10.1 was then used to extract fundamental gully morphological parameters covering gully length (L), gully width (WT) and gully depth (D), and some derivative morphological parameters, including gully head curvature (C), gully width–depth ratio (w/d), gully bottom‐to‐top width ratio (WB/WT), gully surface area (Ag) and gully volume (Vg). The results indicated that gullies in the upper watershed and the second order were more developed based on their high values of gully head curvature. The potential for gully development increased from the second order to the fourth order. Within the same gully orders, gullies in the lower watershed were more active with more development potential. A method for differentiating between gully head and gully sidewalls based on the gully head curvature value was proposed with a mean relative error of 8.77%. U‐shaped cross‐sections were widely distributed in the upper watershed and upper positions of a gully, while V‐shaped cross‐sections were widely distributed in the lower watershed and lower positions of a gully. V–L and V–Ag empirical equations with acceptable accuracy were established and can be used to estimate gully erosion in the Loess hilly‐gully region. Copyright © 2017 John Wiley & Sons, Ltd.

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Section: Gully Cross-sectionsupporting

confidence: 85%

Gully morphological characteristics in the loess hilly‐gully region based on 3D laser scanning technique

Zheng

et al. 2018

Earth Surf Processes Landf

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“…The distribution of different skewed types in different sites is shown in Table 1. In Julin, Laoyatang, and Maoyi, the quantity of right skewed gullies is greater than that of left skewed ones, which is similar to the cross-sections (Deng et al, 2015). The shape ratio (Sr) represents the difference between the plane form of the gully and a square with the same area as the gully.…”

Section: Proportional Characteristicsmentioning

confidence: 74%

“…In the Northern Hemisphere, under the influence of the Coriolis force, the direction of objects' movements is right skewed, which clearly causes serious erosion of the right banks of rivers. The flow of water in the gullies has a short distance and the Coriolis force is very small, but the force still has an effect on the gully erosion; however, we cannot determine its contribution to the phenomenon of the dominance of the right skewed gully type (Deng et al, 2015). In addition, the symmetry of the gully plane form is also synthetically affected by the topography, vegetation, soil properties, and human activities.…”

Section: Discussionmentioning

confidence: 95%

“…Based on the symmetry index, the gullies are divided into left skewed, right skewed, and symmetric types. In the Yuanmou Dry-hot Valley, the right skewed gullies are in the majority (Deng et al, 2015). In the Northern Hemisphere, under the influence of the Coriolis force, the direction of objects' movements is right skewed, which clearly causes serious erosion of the right banks of rivers.…”

Section: Discussionmentioning

confidence: 99%

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Planar morphology and controlling factors of the gullies in the Yuanmou Dry-hot Valley based on field investigation

et al. 2015

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The plane form of a gully can provide a basis for evaluating the gully volume and erosion rate, acting process, and evolutionary stage. For describing the planar characteristics of a permanent gully and understanding their controlling factors, this study, utilizing a total station and GPS RTK, measured the shoulder lines and channel curves of 112 gullies in six sites of the Yuanmou Dry-hot Valley and then mapped them by ArcGIS software and calculated nine parameters. The results showed that the channel lengths range from 10.88 to 249.11 m; the widths range from 6.20 to 40.99 m; the perimeters range from 54.11 to 541.67 m; the gully areas range from 153.02 to 6,930.30 m 2 ; the left-side areas range from 92.93 to 4,027.20 m 2 ; and the right-side areas range from 63.65 to 3,539.77 m 2 . The slightly sinuous and straight gullies account for 73.21% of the total gullies; the quantity of the right skewed gullies is 8.93% greater than that of the left skewed ones based on the symmetry ratio; the shape ratios range from 1.12 to 1.40 and the morphology ratios from 0.038 to 1.294; the fractal dimension is 1.192. Gullies in different sites have diverse planar characteristics. Except for the symmetry index, which was close to a negatively skewed distribution, all of the other parameters had the characteristic of positively skewed distribution. The gully area is related to the length and width, but the gully length has a weak correlation with the width. The evolutionary stage, topographic conditions, strata, soil properties, and piping erosion played very important roles in the gully planar morphology. This study could provide useful information for controlling gully erosion and safeguarding human habitation and engineering buildings.

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“…Previous studies on gully morphology have mostly focused on the cross-sectional or longitudinal profile (Billi & Dramis, 2003;Cheng et al, 2007;Deng, Qin, et al, 2015;Gabet & Bookter, 2008;Valentin, Poesen, & Li, 2005;Vandekerckhove et al, 2000;Zhang, Wu, Liu, Zheng, & Yin, 2007), but the shoulder line typically lacks planar morphology (Deng, Miao, et al, 2015). Compared with accuracy assessments based on gully length, area, and volume (Perroy et al, 2010), this study focused on the gully shape described by fractal dimension.…”

Section: Introductionmentioning

confidence: 99%

Influences of different surveying and mapping methods on fractal characteristics of gully-head shoulder lines

et al. 2016

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2016): Influences of different surveying and mapping methods on fractal characteristics of gully-head shoulder lines, Physical Geography, ABSTRACT Accurate quantification of gully shoulder lines (gully borderlines) will help better understand gully formation and evolution. Surveying and mapping are the most important ways to obtain precise morphology. To evaluate the influences of different steps of surveying and of curvefitting methods of mapping on the morphology of the shoulder line characterized by fractal dimensions, 13 shoulder lines at gully heads were surveyed using a total station and then mapped with different methods of curve fitting, with the fractal dimensions calculated by maps compared with those measured in the field. Fractal dimensions by field measurement ranged from 1.185 to 1.456. Compared with field measurements, the average absolute errors of polygonal line, quadratic B-spline, and arc-fitting methods are 0.045, 0.040, and 0.046, respectively; the average relative errors are 3.48, 3.13, and 3.59%. Therefore, the quadratic B-spline method has a higher accuracy. The standard error of the fractal dimension tends to be larger as average step length increases. The error is ~5% when the step length is 0.7 m, which is advisable for field surveying. This study will help promote the efficiency of field surveying and mapping, and thus promote the accuracy and credibility of gully morphology.

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Characterizing the morphology of gully cross-sections based on PCA: A case of Yuanmou Dry-Hot Valley

Cited by 82 publications

References 50 publications

Gully morphological characteristics in the loess hilly‐gully region based on 3D laser scanning technique

Gully morphological characteristics in the loess hilly‐gully region based on 3D laser scanning technique

Planar morphology and controlling factors of the gullies in the Yuanmou Dry-hot Valley based on field investigation

Influences of different surveying and mapping methods on fractal characteristics of gully-head shoulder lines

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