Quantitative morphometric analysis of lakes using GIS: rectangularityR, ellipticityE, orientationO, and the rectangularity vs. ellipticity index, REi

Lombardo, Umberto

doi:10.1080/15230406.2014.919540

Cited by 7 publications

(5 citation statements)

References 39 publications

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“…To evaluate the degree to which a landslide is elliptical, we use an ellipticity index ( e ) developed by Lombardo () for measuring lake shape and adapt it for landslide shapes:

e_{L} = 1 - 2 \frac{A_{L} - A_{L \cap E}}{A_{L}}

where e L = landslide ellipticity index, A L = original landslide area, ∩ represents ‘intersection’, and A L∩E = area of geometrical intersection (hashed areas in Figure ) between original landslide shape ( L ) and its idealised elliptic shape ( E ). The quantity ( A L − A L∩E ) is the landslide area not covered by the ellipse.…”

Section: Methodsmentioning

confidence: 99%

“…To evaluate the degree to which a landslide is elliptical, we use an ellipticity index (e) developed by Lombardo (2014) for measuring lake shape and adapt it for landslide shapes:…”

Section: Ellipticity Indexmentioning

confidence: 99%

“…Across many disciplines, considerable effort has been devoted to the development of methodologies to measure shape (Barrett, 1980;Li et al, 2001;Benediktsson et al, 2003;Adams et al, 2004;Slice, 2007). Methods to quantify shape include (i) geometric morphometric techniques, based on digitising a set of key points on a shape, and examining the relationships between those points (Adams and Rohlf, 2000), (ii) shape indices, which examine relationships between area and perimeter of shapes (Li et al, 2001), and (iii) shape similarity measures where irregular shapes are compared with regular shapes (Lombardo, 2014).…”

Section: Introductionmentioning

confidence: 99%

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Landslide shape, ellipticity and length‐to‐width ratios

Taylor

Malamud

Witt

et al. 2018

Earth Surf Processes Landf

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This paper presents a new methodology to systematically quantify the shape of landslides by their ellipticity (eL) and length‐to‐width ratio (ΛL), along with variability in these measures over different geomorphic settings. Two large substantially complete triggered‐event landslide inventories (source area and runout) are used: (i) 11 111 earthquake‐triggered landslides (1994 Northridge, USA); and (ii) 9594 rainfall‐triggered landslides (1998, Guatemala). Three methods are trialled to abstract landslide shapes to ellipses. The best method fits a convex hull to each landslide shape, approximates an ellipse with the equivalent convex hull area and perimeter, and scales this ellipse to match the original landslide area. An ellipticity index (eL) is used based on the intersection of the original landslide shape and the elliptical approximation. We consider an ellipse a reasonable approximation of landslide shape if eL ≥ 0.5 (>80% of landslides in each of the two landslide inventories). Landslides with eL < 0.5 reflect processes such as coalescence. We calculate for each landslide an ellipse length‐to‐width ratio (ΛE), finding 1.2 ≤ ΛE ≤ 15.1. The statistical distributions of ΛE are examined for ten categories of landslide area (AL). An inverse‐Gamma probability density function is found to be a good statistical model for landslide ΛE, with model parameters dependent on landslide area category. As landslide area AL increases, ΛE tends to decrease for the Northridge (earthquake‐triggered) inventory and increase for Guatemala (rainfall‐triggered). In three additional (rainfall‐triggered) landslide inventories, ΛE trends are similar to Guatemala. Our findings show that (i) an ellipse is a reasonable model for >80% of landslide shapes across different geomorphic settings, (ii) those landslides significantly deviating from an ellipse can be related to landscape processes, (iii) the length‐to‐width ratios of ellipses are non‐normally distributed, with implications for modelling landslide hazard and risk. Supporting information includes code so that the new methodology may be applied more widely. © 2018 John Wiley & Sons, Ltd.

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“…To evaluate the degree to which a landslide is elliptical, we use an ellipticity index ( e ) developed by Lombardo () for measuring lake shape and adapt it for landslide shapes:

e_{L} = 1 - 2 \frac{A_{L} - A_{L \cap E}}{A_{L}}

Section: Methodsmentioning

confidence: 99%

“…To evaluate the degree to which a landslide is elliptical, we use an ellipticity index (e) developed by Lombardo (2014) for measuring lake shape and adapt it for landslide shapes:…”

Section: Ellipticity Indexmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Landslide shape, ellipticity and length‐to‐width ratios

Taylor

Malamud

Witt

et al. 2018

Earth Surf Processes Landf

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“…Where 𝑖 is the ID of the plantation (block ID); 𝑁 is the number of vertices of the plantation (e.g., triangle: NSCP=3-gon; rectangle: NSCP=4-gon; pentagon: NSCP=5-gon); 𝑃𝑒𝑟𝑖𝑚𝑒𝑡𝑒𝑟 is the length of the perimeter of the plantation; 𝐴𝑟𝑒𝑎 is the area of the plantation; and 𝑚𝑖𝑛. 𝐴𝑟𝑒𝑎 is the minimum bounding area in a rectangle (algorithm sources: McGarigal et al 2012;Moser et al 2002;Lombardo 2014).…”

Section: Surrounding Landscapementioning

confidence: 99%

Land-use patterns of energy crops in the agricultural landscape

Xu¹

2023

Diss. For.

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Lignocellulosic energy crops can produce substantial amounts of biomass for energy purposes, but their introduction implies land-use changes as they are mainly cultivated in agriculturally dominated landscapes. This thesis presents a land-use analysis of lignocellulosic energy crops in the agricultural landscape in Sweden, specifically aiming to i) assess different energy crops’ regarding production, location and climatic profiles, ii) characterise and define the surrounding agricultural landscape, and iii) study the overall land-use changes derived from the establishment of energy crops in the country. The analysis is based on empirical data from commercial fast-growing tree plantations (willow, poplar, and hybrid aspen) and energy grasses (reed canary grass) at multiple spatial scales from field to landscape level, during the period 1986-2018. At field level, there is a trend for smaller and more regular fields dedicated to energy crops, with cultivation patterns moving towards more productive lands, reflecting an intensification in the land-use management. Willow was initially established mainly on fallow lands, but many plantations were subsequently replaced by cereals due to changes in global cereal prices. In the case of grasses, this pattern was similar, although changes appeared later and not so markedly. At landscape level, energy crops significantly diversify the agricultural landscape, as fast-growing tree plantations are largely introduced in cereal areas and grasses in forest-dominated landscapes. The methods and analysis of this thesis contribute to a better understanding of land-use changes associated to energy crops, and help define their contribution to diversifying the agricultural landscape.

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“…El uso de equipos automatizados para medir la morfología y sedimentos de los lagos en comparación con métodos tradicionales, ahorra tiempo y ofrece mayor precisión (Lombardo, 2014;Martínez et al, 2015) y si se tienen sistematizados una importante cantidad de datos permiten estructurar modelos predictivos y pronosticar posibles efectos de sus cambios en el futuro.…”

Section: Introductionunclassified

Caracterización morfobatimétrica y estimación de sedimentos de la bahía interior de Puno, lago Titicaca, mediante tecnología SIG

Carpio¹,

Peralta²,

Aliaga³

2016

Rev. Investig. Altoandin. - RIA -

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Los ecosistemas lénticos, tienden a sufrir cambios morfométricos y batimétricos con el paso del tiempo. Esta condición en la bahía interior de Puno, aún no ha sido detallada, por lo que el presente conllevó a su caracterización en los años 2010 y 2012, para compararla con la del año 1975, además de estimar el volumen de sedimento acumulado en el lecho lacustre desde esa fecha. Para esto se digitalizaron las cartas batimétricas de 1975 y se hicieron levantamientos actuales mediante el uso de ecosonda y aplicación de tecnologías SIG; luego se trazaron isóbatas y construyeron mapas para comparar las variaciones. La estimación de sedimentos acumulados se realizó por diferencias de volumen de agua y cambios de profundidad entre los años mencionados. Los resultados refieren que las condiciones batimétricas han cambiado relativamente, manteniendo un fondo lacustre irregular, con profundidades máximas de 7.76 m para 1975, 7.07 m para 2010 y 7.19 para el 2012. Sus mayores áreas están ocupadas por profundidades menores a 1 m y los mayores volúmenes en las profundidades de 3 a 4 m. Los perfiles evidencian que la cubeta tiene un talud con mayor profundidad hacia la ciudad de Puno. El área para 1975 fue de 15.79 km2 y para el 2012 de 15.9 km2; para el 2012 el volumen fue de 39 millones de m3, menor a 1975 que superó los 42 millones. El volumen de sedimentos acumulado desde 1975 hasta el año 2012 fue de 887352.02 m3, siendo la tasa de acumulación de 23982.48 m3/año y 4.1 mm/año.

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Quantitative morphometric analysis of lakes using GIS: rectangularityR, ellipticityE, orientationO, and the rectangularity vs. ellipticity index, REi

Cited by 7 publications

References 39 publications

Landslide shape, ellipticity and length‐to‐width ratios

Landslide shape, ellipticity and length‐to‐width ratios

Land-use patterns of energy crops in the agricultural landscape

Caracterización morfobatimétrica y estimación de sedimentos de la bahía interior de Puno, lago Titicaca, mediante tecnología SIG

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