scholarly journals FracL: A Tool for Characterizing the Fractality of Landscape Gradients from a New Perspective

2019 ◽  
Vol 8 (10) ◽  
pp. 466 ◽  
Author(s):  
Peichao Gao ◽  
Samuel A. Cushman ◽  
Gang Liu ◽  
Sijing Ye ◽  
Shi Shen ◽  
...  
Keyword(s):  
Landscape Ecology ◽  
Fractal Analysis ◽  
Real Life ◽  
Digital Terrain Model ◽  
Technical Note ◽  
Landscape Patterns ◽  
Terrain Model ◽  
Landscape Gradients ◽  
New Perspective ◽  
Definition Of

The past several years have witnessed much progress in landscape ecology and fractal analysis. In landscape ecology, the gradient model of landscape patterns (i.e., landscape gradient) has emerged as a new operating paradigm, where most landscape metrics do not apply because they were developed for the patch mosaic model. In the fractal analysis, a new definition of fractal has been proposed, and various new fractal metrics have been developed. This technical note aims to provide an intersection of these two lines of advance, which will further present an opportunity to advance geo-informatics by considering the latest progress in both landscape ecology and fractal analysis. We first present an overview of the new definition of fractal and all the fractal metrics developed under this new definition. Since the chief obstacle to geographers and landscape ecologists in applying these metrics is the lack of readily accessible methods for their easy computation, we then develop an integrated tool to compute them on landscape gradients. The developed tool facilitates the computation of these new fractal metrics. A case study was carried out with real-life landscape gradients, namely a digital terrain model. These new fractal metrics and the developed tool can be expected to facilitate the fractal characterization of the patterns of gradient landscapes and the understanding of landscape dynamics from a new perspective.

scholarly journals Technical Note: Preliminary estimation of rockfall runout zones

2011 ◽  
Vol 11 (3) ◽  
pp. 819-828 ◽  
Author(s):  
M. Jaboyedoff ◽  
V. Labiouse
Keyword(s):  
Slope Angle ◽  
Digital Terrain Model ◽  
Grid Cell ◽  
Technical Note ◽  
Field Observations ◽  
Source Areas ◽  
Terrain Model ◽  
Digital Terrain ◽  
Energy Line ◽  
Potential Source

Abstract. Rockfall propagation areas can be determined using a simple geometric rule known as shadow angle or energy line method based on a simple Coulomb frictional model implemented in the CONEFALL computer program. Runout zones are estimated from a digital terrain model (DTM) and a grid file containing the cells representing rockfall potential source areas. The cells of the DTM that are lowest in altitude and located within a cone centered on a rockfall source cell belong to the potential propagation area associated with that grid cell. In addition, the CONEFALL method allows estimation of mean and maximum velocities and energies of blocks in the rockfall propagation areas. Previous studies indicate that the slope angle cone ranges from 27° to 37° depending on the assumptions made, i.e. slope morphology, probability of reaching a point, maximum run-out, field observations. Different solutions based on previous work and an example of an actual rockfall event are presented here.

scholarly journals Hydrological characterization of the Usumacinta River Basin towards the preservation of environmental services

2015 ◽  
Vol XL-7/W3 ◽  
pp. 1505-1509 ◽  
Author(s):  
F.-O. Tapia-Silva ◽  
A.-I. Contreras-Silva ◽  
E.-R. Rosales-Arriaga
Keyword(s):  
Vegetation Cover ◽  
Hydrological Cycle ◽  
Digital Terrain Model ◽  
Channel Length ◽  
Biophysical Parameters ◽  
Map Algebra ◽  
Ecosystem Monitoring ◽  
Terrain Model ◽  
Digital Terrain ◽  
Definition Of

The Usumacinta basin is characterized by aboundance of natural and scenic resources. It also houses a vast biodiversity (wich also means invaluable genetic resources). Its river is the longest in Mexico (main channel length of 927 km). Therefore it is one of the most productive regions of the country in terms of ecosystem services (such as habitat for biodiversity, maintenance of wetlands, water flows generation, carbon sequestration, soil retention, etc.) that are directly related to the hydrological functioning. During the last centuries, human activities on the Usumacinta basin have drastically changed its geomorphology and vegetation cover. As a result the hydrological cycle has been greatly modified. Therefore, it is necessary to conduct studies in order to support planning activities and implementation of public policies, as well as, to generate a permanent scientific ecosystem monitoring system. <br><br> This paper presents the results of a study focused on estimating the water balance of this frontier basin. Satellite and field data is used. Variables as vegetation cover (generated by classification of Landsat and MODIS), digital terrain model (SRTM), surface temperature (MODIS), potential evaporation, precipitation and runoff measurements were processed. Various techniques of Remote Sensing, geospatial models (as SSEB and the model for definition of surface hydrological connectivity) and spatial analysis (geostatistics and map algebra) were implemented. The results were integrated into the environment of a Geographic Information System. These are estimates of actual evapotranspiration, soil moisture and runoff, among other biophysical parameters. For the lower part of the basin a balance was performed to estimate inputs of water from runoff and precipitation to the large amount of wetlands in the area. Additionally, areas generating runoff and areas in which most of the precipitaion infiltrates were also mapped. The geo-information obtained is requiered for purposes of planning and land management.

scholarly journals Estimating Pasture Biomass and Canopy Height in Brazilian Savanna Using UAV Photogrammetry

2019 ◽  
Vol 11 (20) ◽  
pp. 2447 ◽  
Author(s):  
Juliana Batistoti ◽  
José Marcato Junior ◽  
Luís Ítavo ◽  
Edson Matsubara ◽  
Eva Gomes ◽  
...  
Keyword(s):  
Digital Terrain Model ◽  
Technical Note ◽  
Canopy Height ◽  
Brazilian Savanna ◽  
Surface Model ◽  
Panicum Maximum ◽  
Ground Sample ◽  
Terrain Model ◽  
Sampling Height ◽  
The Difference

The Brazilian territory contains approximately 160 million hectares of pastures, and it is necessary to develop techniques to automate their management and increase their production. This technical note has two objectives: First, to estimate the canopy height using unmanned aerial vehicle (UAV) photogrammetry; second, to propose an equation for the estimation of biomass of Brazilian savanna (Cerrado) pastures based on UAV canopy height. Four experimental units of Panicum maximum cv. BRS Tamani were evaluated. Herbage mass sampling, height measurements, and UAV image collection were simultaneously performed. The UAVs were flown at a height of 50 m, and images were generated with a mean ground sample distance (GSD) of approximately 1.55 cm. The forage canopy height estimated by UAVs was calculated as the difference between the digital surface model (DSM) and the digital terrain model (DTM). The R2 between ruler height and UAV height was 0.80; between biomass (kg ha−1 GB—green biomass) and ruler height, 0.81; and between biomass (kg ha−1 GB) and UAV height, 0.74. UAV photogrammetry proved to be a potential technique to estimate height and biomass in Brazilian Panicum maximum cv. BRS Tamani pastures located in the endangered Brazilian savanna (Cerrado) biome.

scholarly journals Možnosti srovnávací analýzy plužiny zaniklých středověkých vsí. Vypovídací hodnota vybraných lokalit a role digitálního modelu reliéfu z dat leteckého laserového skenování

2021 ◽  
Vol 6 (1-2) ◽  
pp. 177-196
Author(s):  
Ondřej Malina ◽  
Lukáš Holata ◽  
Jindřich Plzák
Keyword(s):  
Laser Scanning ◽  
Digital Terrain Model ◽  
Specific Data ◽  
Archaeological Heritage ◽  
Terrain Model ◽  
Digital Terrain ◽  
Airborne Laser ◽  
Data Source ◽  
Definition Of

The paper deals with the plowlands of deserted medieval villages (DMVs) representing a specific data source of medieval settlement research. Its basic priorities are based on the needs of archaeological heritage protection for a better definition of DMVs’ hinterlands, which are significantly less distinguishable in comparison with villages’ intravilans. At the same time, not much attention was paid to this area, even in known or well-surveyed sites. These issues are important especially in the context of what exactly we are looking for within the DMVs, how we define it and where we can find the best examples worthy of protection or further study. The basis of the presented work is the processing of a digital terrain model derived from airborne laser scanning data. The primary procedure consists of the ALS data processing into a DEM, its subsequent visualization, and classification of objects in DMVs’ hinterlands, which is further supplemented by selected examples of field verification. The informative value of the hinterlands is also discussed on the example of several differently preserved sites.

scholarly journals Information Theory as a consistent framework for quantification and classification of landscape patterns

2018 ◽  
Author(s):  
Jakub Nowosad ◽  
Tomasz F. Stepinski
Keyword(s):  
Information Theory ◽  
Landscape Ecology ◽  
Real Life ◽  
Random Variable ◽  
Landscape Patterns ◽  
Life Patterns ◽  
Changing Patterns ◽  
Correlated Information ◽  
The Relationship

AbstractContextQuantitative grouping of similar landscape patterns is an important part of landscape ecology due to the relationship between a pattern and an underlying ecological process. One of the priorities in landscape ecology is a development of the theoretically consistent framework for quantifying, ordering and classifying landscape patterns.ObjectiveTo demonstrate that the Information Theory as applied to a bivariate random variable provides a consistent framework for quantifying, ordering, and classifying landscape patterns.MethodsAfter presenting Information Theory in the context of landscapes, information-theoretical metrics were calculated for an exemplar set of landscapes embodying all feasible configurations of land cover patterns. Sequences and 2D parametrization of patterns in this set were performed to demonstrate the feasibility of Information Theory for the analysis of landscape patterns.ResultsUniversal classification of landscape into pattern configuration types was achieved by transforming landscapes into a 2D space of weakly correlated information-theoretical metrics. An ordering of landscapes by any single metric cannot produce a sequence of continuously changing patterns. In real-life patterns, diversity induces complexity – increasingly diverse patterns are increasingly complex.ConclusionsInformation theory provides a consistent, theory-based framework for the analysis of landscape patterns. Information-theoretical parametrization of landscapes offers a method for their classification.

A renovated model for spatial analysis of pollutant runoff loads in agricultural watershed

1998 ◽  
Vol 38 (10) ◽  
pp. 207-214 ◽  
Author(s):  
Sung Ryong Ha ◽  
Dhong Il Jung ◽  
Cho Hee Yoon
Keyword(s):  
Stream Water ◽  
Digital Terrain Model ◽  
Pollution Sources ◽  
Agricultural Watershed ◽  
Water Model ◽  
Digital Information ◽  
Gis Technology ◽  
Terrain Model ◽  
Unit Loading ◽  
Pollutant Discharge

Runoff loads of pollutant in agricultural watersheds were spatially analyzed by using geographic information system(GIS) technology. The topological relationship between pollution sources in the watershed was, first of all, identified by using the developed digital map of land use and then the pollutant loads generated from each source was estimated by applying a conventional unit loading factor on the obtained digital information of pollution sources. To evaluate the loads delivered from spatially distributed pollution sources to monitoring stations in down stream via surface of watershed, a renovated empirical model incorporated with the information of pollutant discharge path was developed through introducing a digital terrain model(DTM) technique. In this model, the function of degradation of pollution loads during delivery process was simplified so that each watershed could have a basin-wide self-purification capacity which would be considered to be possessed inherently in each watershed and could retard the discharge of pollutants from sources generated to stream water. Model credibility showed good consistency with comparing the simulated values with observed data. Monte Carlo optimizing technique made it possible to estimate the basin-wide self-purification coefficients.

Is Treat-to-target in Lupus Nephritis Realistic in Clinical Practice?

2018 ◽  
Vol 15 (1) ◽  
pp. 2-6 ◽  
Author(s):  
Chi Chiu Mok
Keyword(s):  
Lupus Nephritis ◽  
Disease Activity ◽  
Safety Concern ◽  
Real Life ◽  
Current Treatment ◽  
Treat To Target ◽  
Low Disease Activity ◽  
Activity State ◽  
Definition Of ◽  
Comparative Trials

The Treat-to-Target (T2T) principle has been advocated in a number of inflammatory and non-inflammatory medical illnesses. Tight control of disease activity has been shown to improve the outcome of rheumatoid arthritis and psoriatic arthritis as compared to the conventional approach. However, whether T2T can be applied to patients with lupus nephritis is still under emerging discussion. Treatment of lupus nephritis should target at inducing and maintaining remission of the kidney inflammation so as to preserve renal function and improve survival in the longterm. However, there is no universal agreement on the definition of remission or low disease activity state of nephritis, as well as the time points for switching of therapies. Moreover, despite the availability of objective parameters for monitoring such as proteinuria and urinary sediments, differentiation between ongoing activity and damage in some patients with persistent urinary abnormalities remains difficult without a renal biopsy. A large number of serum and urinary biomarkers have been tested in lupus nephritis but none of them have been validated for routine clinical use. In real life practice, therapeutic options for lupus nephritis are limited. As patients with lupus nephritis are more prone to infective complications, tight disease control with aggressive immunosuppressive therapies may have safety concern. Not until the feasibility, efficacy, safety and cost-effectiveness of T2T in lupus nephritis is confirmed by comparative trials, this approach should not be routinely recommended with the current treatment armamentarium and monitoring regimes.

scholarly journals The Effect of LiDAR Sampling Density on DTM Accuracy for Areas with Heavy Forest Cover

Forests ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 265
Author(s):  
Mihnea Cățeanu ◽  
Arcadie Ciubotaru
Keyword(s):  
Forest Cover ◽  
Initial Point ◽  
Ground Surface ◽  
Digital Terrain Model ◽  
Morphological Data ◽  
Sampling Density ◽  
Terrain Model ◽  
Digital Terrain ◽  
Point Density ◽  
The Impact

Laser scanning via LiDAR is a powerful technique for collecting data necessary for Digital Terrain Model (DTM) generation, even in densely forested areas. LiDAR observations located at the ground level can be separated from the initial point cloud and used as input for the generation of a Digital Terrain Model (DTM) via interpolation. This paper proposes a quantitative analysis of the accuracy of DTMs (and derived slope maps) obtained from LiDAR data and is focused on conditions common to most forestry activities (rough, steep terrain with forest cover). Three interpolation algorithms were tested: Inverse Distance Weighted (IDW), Natural Neighbour (NN) and Thin-Plate Spline (TPS). Research was mainly focused on the issue of point data density. To analyze its impact on the quality of ground surface modelling, the density of the filtered data set was artificially lowered (from 0.89 to 0.09 points/m2) by randomly removing point observations in 10% increments. This provides a comprehensive method of evaluating the impact of LiDAR ground point density on DTM accuracy. While the reduction of point density leads to a less accurate DTM in all cases (as expected), the exact pattern varies by algorithm. The accuracy of the LiDAR-derived DTMs is relatively good even when LiDAR sampling density is reduced to 0.40–0.50 points/m2 (50–60 % of the initial point density), as long as a suitable interpolation algorithm is used (as IDW proved to be less resilient to density reductions below approximately 0.60 points/m2). In the case of slope estimation, the pattern is relatively similar, except the difference in accuracy between IDW and the other two algorithms is even more pronounced than in the case of DTM accuracy. Based on this research, we conclude that LiDAR is an adequate method for collecting morphological data necessary for modelling the ground surface, even when the sampling density is significantly reduced.

scholarly journals DTM-based analysis of the spatial distribution of topolineaments

2020 ◽  
Vol 12 (1) ◽  
pp. 1185-1199
Author(s):  
Mirosław Kamiński
Keyword(s):  
Laser Scanning ◽  
Digital Terrain Model ◽  
Research Area ◽  
Tectonic Structures ◽  
Empirical Bayesian ◽  
Scanning Method ◽  
Empirical Bayesian Kriging ◽  
Terrain Model ◽  
Digital Terrain ◽  
Airborne Laser

AbstractThe research area is located on the boundary between two Paleozoic structural units: the Radom–Kraśnik Block and the Mazovian–Lublin Basin in the southeastern Poland. The tectonic structures are separated by the Ursynów–Kazimierz Dolny fault zone. The digital terrain model obtained by the ALS (Airborne Laser Scanning) method was used. Classification and filtration of an elevation point cloud were performed. Then, from the elevation points representing only surfaces, a digital terrain model was generated. The model was used to visually interpret the course of topolineaments and their automatic extraction from DTM. Two topolineament systems, trending NE–SW and NW–SE, were interpreted. Using the kernel density algorithm, topolineament density models were generated. Using the Empirical Bayesian Kriging, a thickness model of quaternary deposits was generated. A relationship was observed between the course of topolineaments and the distribution and thickness of Quaternary formations. The topolineaments were compared with fault directions marked on tectonic maps of the Paleozoic and Mesozoic. Data validation showed consistency between topolineaments and tectonic faults. The obtained results are encouraging for further research.

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