scholarly journals SaLEM (v1.0) – the Soil and Landscape Evolution Model (SaLEM) for simulation of regolith depth in periglacial environments

2018 ◽  
Vol 11 (4) ◽  
pp. 1641-1652
Author(s):  
Michael Bock ◽  
Olaf Conrad ◽  
Andreas Günther ◽  
Ernst Gehrt ◽  
Rainer Baritz ◽  
...  
Keyword(s):  
Landscape Evolution ◽  
Initial Conditions ◽  
Digital Terrain Model ◽  
Test Site ◽  
Parent Material ◽  
Evolution Model ◽  
Geographical Information ◽  
Future Research ◽  
Terrain Model ◽  
Soil Parent Material

Abstract. We propose the implementation of the Soil and Landscape Evolution Model (SaLEM) for the spatiotemporal investigation of soil parent material evolution following a lithologically differentiated approach. Relevant parts of the established Geomorphic/Orogenic Landscape Evolution Model (GOLEM) have been adapted for an operational Geographical Information System (GIS) tool within the open-source software framework System for Automated Geoscientific Analyses (SAGA), thus taking advantage of SAGA's capabilities for geomorphometric analyses. The model is driven by palaeoclimatic data (temperature, precipitation) representative of periglacial areas in northern Germany over the last 50 000 years. The initial conditions have been determined for a test site by a digital terrain model and a geological model. Weathering, erosion and transport functions are calibrated using extrinsic (climatic) and intrinsic (lithologic) parameter data. First results indicate that our differentiated SaLEM approach shows some evidence for the spatiotemporal prediction of important soil parental material properties (particularly its depth). Future research will focus on the validation of the results against field data, and the influence of discrete events (mass movements, floods) on soil parent material formation has to be evaluated.

scholarly journals SaLEM (v1.0) – A Soil and Landscape Evolution Model for simulation of regolith depth in periglacial environments

2017 ◽  
Author(s):  
Michael Bock ◽  
Olaf Conrad ◽  
Andreas Günther ◽  
Ernst Gehrt ◽  
Rainer Baritz ◽  
...  
Keyword(s):  
Landscape Evolution ◽  
Initial Conditions ◽  
Digital Terrain Model ◽  
Test Site ◽  
Parent Material ◽  
Evolution Model ◽  
Future Research ◽  
Climatic Data ◽  
Terrain Model ◽  
Soil Parent Material

Abstract. We propose the implementation of a soil and landscape evolution model (SaLEM) for the spatiotemporal investigation of soil parent material evolution following a lithologically differentiated approach. Relevant parts of the established model GOLEM have been adapted for an operational GIS tool within the open source software framework SAGA, thus taking advantage of SAGA's capabilities for geomorphometric analyses. The model is driven by paleo-climatic data (temperature, precipitation) representative for periglacial areas in Northern Germany over the last 50.000 years. The initial conditions have been determined for a test site by a digital terrain model and a geological model. Weathering, erosion and transport functions are calibrated using extrinsic (climatic) and intrinsic (lithologic) parameter data. First results indicate that our differentiated SaLEM approach shows some evidence for the spatiotemporal prediction of important soil parental material properties particularly its depth. Future research will focus on the v alidation of the results against field data, and the influence of discrete events (mass movements, floods) on soil parent material formation has to be evaluated.

scholarly journals Scaling and similarity of a stream-power incision and linear diffusion landscape evolution model

2018 ◽  
Vol 6 (3) ◽  
pp. 779-808 ◽  
Author(s):  
Nikos Theodoratos ◽  
Hansjörg Seybold ◽  
James W. Kirchner
Keyword(s):  
Steady State ◽  
Peclet Number ◽  
Degrees Of Freedom ◽  
Landscape Evolution ◽  
Initial Conditions ◽  
Evolution Model ◽  
Model Parameters ◽  
Stream Power ◽  
Linear Diffusion ◽  
Characteristic Scales

Abstract. The scaling and similarity of fluvial landscapes can reveal fundamental aspects of the physics driving their evolution. Here, we perform a dimensional analysis of the governing equation of a widely used landscape evolution model (LEM) that combines stream-power incision and linear diffusion laws. Our analysis assumes that length and height are conceptually distinct dimensions and uses characteristic scales that depend only on the model parameters (incision coefficient, diffusion coefficient, and uplift rate) rather than on the size of the domain or of landscape features. We use previously defined characteristic scales of length, height, and time, but, for the first time, we combine all three in a single analysis. Using these characteristic scales, we non-dimensionalize the LEM such that it includes only dimensionless variables and no parameters. This significantly simplifies the LEM by removing all parameter-related degrees of freedom. The only remaining degrees of freedom are in the boundary and initial conditions. Thus, for any given set of dimensionless boundary and initial conditions, all simulations, regardless of parameters, are just rescaled copies of each other, both in steady state and throughout their evolution. Therefore, the entire model parameter space can be explored by temporally and spatially rescaling a single simulation. This is orders of magnitude faster than performing multiple simulations to span multidimensional parameter spaces. The characteristic scales of length, height and time are geomorphologically interpretable; they define relationships between topography and the relative strengths of landscape-forming processes. The characteristic height scale specifies how drainage areas and slopes must be related to curvatures for a landscape to be in steady state and leads to methods for defining valleys, estimating model parameters, and testing whether real topography follows the LEM. The characteristic length scale is roughly equal to the scale of the transition from diffusion-dominated to advection-dominated propagation of topographic perturbations (e.g., knickpoints). We introduce a modified definition of the landscape Péclet number, which quantifies the relative influence of advective versus diffusive propagation of perturbations. Our Péclet number definition can account for the scaling of basin length with basin area, which depends on topographic convergence versus divergence.

scholarly journals EVALUATING ERROR OF LIDAR DERIVED DEM INTERPOLATION FOR VEGETATION AREA

2016 ◽  
Vol XLII-4/W1 ◽  
pp. 141-150 ◽  
Author(s):  
Z. Ismail ◽  
M. F. Abdul Khanan ◽  
F. Z. Omar ◽  
M. Z. Abdul Rahman ◽  
M. R. Mohd Salleh
Keyword(s):  
Spatial Resolution ◽  
Accuracy Assessment ◽  
Digital Terrain Model ◽  
Geographical Information ◽  
Interpolation Methods ◽  
Terrain Model ◽  
Digital Terrain ◽  
Digital Elevation ◽  
Elevation Model ◽  
Slope Class

Light Detection and Ranging or LiDAR data is a data source for deriving digital terrain model while Digital Elevation Model or DEM is usable within Geographical Information System or GIS. The aim of this study is to evaluate the accuracy of LiDAR derived DEM generated based on different interpolation methods and slope classes. Initially, the study area is divided into three slope classes: (a) slope class one (0° – 5°), (b) slope class two (6° – 10°) and (c) slope class three (11° – 15°). Secondly, each slope class is tested using three distinctive interpolation methods: (a) Kriging, (b) Inverse Distance Weighting (IDW) and (c) Spline. Next, accuracy assessment is done based on field survey tachymetry data. The finding reveals that the overall Root Mean Square Error or RMSE for Kriging provided the lowest value of 0.727 m for both 0.5 m and 1 m spatial resolutions of oil palm area, followed by Spline with values of 0.734 m for 0.5 m spatial resolution and 0.747 m for spatial resolution of 1 m. Concurrently, IDW provided the highest RMSE value of 0.784 m for both spatial resolutions of 0.5 and 1 m. For rubber area, Spline provided the lowest RMSE value of 0.746 m for 0.5 m spatial resolution and 0.760 m for 1 m spatial resolution. The highest value of RMSE for rubber area is IDW with the value of 1.061 m for both spatial resolutions. Finally, Kriging gave the RMSE value of 0.790m for both spatial resolutions.

scholarly journals Internet-based Land Valuation System Powered by a GIS of 1:10,000 Soil Maps

2006 ◽  
Vol 55 (1) ◽  
pp. 109-116 ◽  
Author(s):  
Tibor Tóth ◽  
T. Németh ◽  
T. Fábián ◽  
T. Hermann ◽  
E. Horváth ◽  
...  
Keyword(s):  
Digital Terrain Model ◽  
Geographical Information ◽  
Aerial Photographs ◽  
Topographic Map ◽  
Soil Maps ◽  
Terrain Model ◽  
Land Taxation ◽  
Digital Terrain ◽  
Land Valuation ◽  
Automated Algorithms

An internet-based land valuation system is being developed to replace the scientifically obsolete Hungarian land valuation system, the so-called AK (“Gold Crown”) ratings. The new system is supported by a GIS and it is unique in its capability of providing an up-to-date index of soil quality and land value. The geographical information is provided by national map databases on genetic soil maps and soil attributes at the scale of 1:10.000, combined with cadastral maps, digital terrain model, topographic map, orthophotos of aerial photographs and agronomic field records. The automated algorithms are easy to update, can be made legally binding and can provide a transparent system for land taxation, calculation of subsidies, appropriation. Given that detailed (1:10,000 or finer) soil map coverage will be completed for all lands of Hungary (at date only 60% of the croplands have soil maps), this way a multifunctional system will be available that promotes an optimum use of land resources. 

scholarly journals Comparison of methodologies for automatic generation of limits and drainage networks for hidrographic basins

2009 ◽  
Vol 13 (4) ◽  
pp. 369-375 ◽  
Author(s):  
Samantha A. Alcaraz ◽  
Christophe Sannier ◽  
Antonio C. T. Vitorino ◽  
Omar Daniel
Keyword(s):  
Digital Terrain Model ◽  
Automatic Generation ◽  
Geographical Information ◽  
Stream Network ◽  
Terrain Model ◽  
Digital Terrain ◽  
Contour Lines ◽  
Drainage Networks ◽  
Selection Of

The objective of this work was to compare methodologies for the automatic generation of limits and drainage networks, using a geographical information system for basins of low relief variation, such as the Dourados catchment area. Various data/processes were assessed, especially the ArcHydro and AVSWAT interfaces used to process 50 m resolution DTMs formed from the interpolation of digitalized contour lines using ArcInfo, ArcView and Spring GIS, and a 90 m resolution SRTM DTM acquired by interferometry radar. Their accuracy was estimated based upon the pre-processing of small basic sub-basin units of different relief variations, before applying the best combinations to the entire Dourados basin. The accuracy of the automatic stream network generation and watershed delineation depends essentially on the quality of the raw digital terrain model. The selection of the most suitable one then depends completely on the aims of the user and on the work scale.

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.

GRAINSIZE DEPENDENT TRANSPORT AND DEPOSITION IN A LANDSCAPE EVOLUTION MODEL

2019 ◽  
Author(s):  
Erica Emry ◽  
◽  
Kyungdoe Han ◽  
Michael Berry ◽  
Jolante van Wijk ◽  
...  
Keyword(s):  
Landscape Evolution ◽  
Evolution Model ◽  
Dependent Transport

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.

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