Landscape Topography Research Articles

A new probability-embodied model for simulating variable contributing areas and hydrologic processes dominated by surface depressions

Surface depressions play an important role in overland flow generation, infiltration, and other hydrologic processes. They undergo filling, spilling, and merging during rainfall/snowmelt events, affecting hydrologic connectivity and the size of the contributing area. However, such variability is often ignored or oversimplified in traditional hydrologic models. Consequently, they fail to simulate the threshold-controlled overland flow dynamics. The goal of this study is to improve hydrologic modeling, especially for depression-dominated areas, by capturing the variable contributing area and the threshold behavior of overland flow. To achieve this goal, a new depression-oriented variable contributing area (D-VCA) model is developed to simulate the contributing area, runoff dynamics, and their likelihood of occurrence. Specifically, the D-VCA model integrates the simulation of hydrologic processes with a surface topographic analysis procedure, which is able to (1) determine the probability distribution functions of depression storage and the corresponding contributing area and (2) examine the intrinsic changing patterns of depression storage and contributing area. The model was applied to a depression-dominated watershed in North Dakota and its performance was evaluated by comparing the simulated and observed discharges at two USGS gaging stations. The improved performance of the D-VCA model was demonstrated by comparing different modeling methods including the widely-used lumped depression approach. Modeling results demonstrated the unique capabilities of the D-VCA model in simulating depression-influenced overland flow dynamics and the associated threshold behavior. The new model also provides an improved understanding of the evolution of contributing areas and their influence on overland flow generation across different topographic landscapes.

Topographic disequilibrium, landscape dynamics and active tectonics: an example from the Bhutan Himalaya

Abstract. The quantification of active tectonics from geomorphological and morphometric approaches commonly implies that erosion and tectonics have reached a certain balance. Such equilibrium conditions are however rare in nature, as questioned and documented by recent theoretical studies indicating that drainage basins may be perpetually re-arranging even though tectonic and climatic conditions remain constant. Here, we document these drainage dynamics in the Bhutan Himalaya, where evidence for out-of-equilibrium morphologies have for long been noticed, from major (> 1 km high) river knickpoints and from high-altitude low-relief regions in the mountain hinterland. To further characterize these morphologies and their dynamics, we perform field observations and a detailed quantitative morphometric analysis using χ plots and Gilbert metrics of drainages over various spatial scales, from major Himalayan rivers to their tributaries draining the low-relief regions. We first find that the river network is highly dynamic and unstable, with much evidence of divide migration and river captures. The landscape response to these dynamics is relatively rapid. Our results do not support the idea of a general wave of incision propagating upstream, as expected from most previous interpretations. Also, the specific spatial organization in which all major knickpoints and low-relief regions are located along a longitudinal band in the Bhutan hinterland, whatever their spatial scale and the dimensions of the associated drainage basins, calls for a common local supporting mechanism most probably related to active tectonic uplift. From there, we discuss possible interpretations of the observed landscape in Bhutan. Our results emphasize the need for a precise documentation of landscape dynamics and disequilibrium over various spatial scales as a first step in morpho-tectonic studies of active landscapes.

Revealing Archaeological Sites under Mediterranean Forest Canopy Using LiDAR: El Viandar Castle (husum) in El Hoyo (Belmez-Córdoba, Spain)

Light detection and Ranging (LiDAR) technology is a valuable tool for archaeological prospection in areas covered by dense vegetation. Its capacity to penetrate dense forest environments enables it to detect archaeological remains scattered over orographically complex areas. LiDAR-derived digital terrain models (DTMs) have made an exceptional contribution towards identifying topographic landscapes of archaeological interest. In this study, we focus on an area of intense historic settlement from the Chalcolithic to the Middle Ages, which today is completely covered by Mediterranean forest. Due to the dense canopy, and the fact that it is a protected area on private land, it has never been analyzed. To reveal the settlement, we primarily used a series of LiDAR mapping surveys to gather data and analyzed other open access remote sensing resources from the National Geographic Institute of Spain (IGN). The IGN LiDAR data proved to be of particular interest. These resources enabled us to detect an ancient fortress (El Viandar Castle) and its surrounding settlement. LiDAR, in conjunction with other products, was fundamental in identifying the site. Equally, the mapping surveys enabled us to analyze the limits and scope of the IGN airborne LiDAR and other free access remote sensing products. Our background in this research demonstrates that low-cost products applied to LiDAR research in archaeology have major limitations when it is necessary to have a high level of spatial resolution in order to define the layout and the main components of an archaeological site.

Birth of a Squatters’ Colony: Revisiting history through refugee narratives

Squatters’ colonies form essential feature of the social, political, cultural and topographic landscape of West Bengal. ‘Destitution and despair’ of East Bengali Hindu refugees as the ‘impetus behind’ and ‘impervious unity and unanimous struggle’ of refugees as the ‘means for success’ in establishment of these colonies have been part of the official account and popular discourse relating to refugee movement in Bengal. Refugee women’s agency in land grabbing movement and counter-eviction struggle are celebrated as the steps towards shattering the patriarchal demarcation between private and public. Present article offers a micro-sociological study of a squatters’ colony, and based on the narratives of real life experiences of colony-people who lived through the struggle of self-rehabilitation, it tends to highlight the varied nature of needs, perceptions and aspirations of refugees; contest and negotiation of power; conflict and clash between selfish/ egoistic interest and community-centred interest; political battles; and patriarchal exploitation of gender roles that were pervasive in the colony life during those days of self-rehabilitation. It also focuses on how the temptation of generalization in meta-narrative analyses tends to obscure the obvious dynamics of life- cohesion versus conflict, exploitation versus subversion of power-politics within the squatters’ colonies, which micro-level social researches may bring forward and thereby signify the scope for re-writing history.

Modeling susceptibility to forest fires in the Central Corridor of the Atlantic Forest using the frequency ratio method

Fire is one of the main disturbances of tropical forests. Understanding the spatial and temporal dynamics of forest fires is of fundamental importance for the conservation of tropical forests. We used a frequency ratio model to identify those areas most susceptible to forest fires in the Central Corridor of the Atlantic Forest, from 2001 to 2019. We used data from the burned area of MODIS MCD64A1 to create the dependent variable grouped as climatic, topographic and human and landscape variables. The receiver operating characteristic (ROC) curve and area under the curve (AUC) were used to assess the model's performance. Land use and relief orientation were the most and least important variables in the model, respectively. The model showed good AUC values, ranging from 0.72 to 0.96, with an average of 0.81 for the study period. The average distribution of susceptibility classes was low (19.62 %), medium (24.45 %) and high (20.55 %). The northwestern region of the CAFC was the one that presented the greatest susceptibility to the occurrence of forest fires. The frequency ratio proved to be a good model for mapping areas susceptible to forest fires in an area of the Atlantic Forest.

Lines of Settlement: Lost Landscapes within Maps for Future Morphologies

The value of archival documents quite often extends beyond their original purpose, as evidence contained within these artefacts, whether written or drawn, can provide veracity for new lines of heritage inquiry. Many settlements in the ‘new world’ were set out by land surveyors whose drawings charted the accurate placement and alignment of new streets and block perimeters laid upon drawings of the extant topographical landscape features. The paper discusses three settlement maps of Melbourne, Australia, through the lens of Michel de Certeau’s idea that maps are an instrument of power are not just about recording; maps are actually about appropriating and producing regimes of place. In the Australian context, the settlement drawings, prepared under the direction of the colonial administration, inadvertently depicts Country that had been under the custodial care of the First Nations peoples for millennia, and through the intentions of the settlement maps about to be irrevocably disturbed, altered or destroyed. We raise the prospect that urban and landscape design can reflect on the ‘lost landscapes’ of cultural significance, and discuss new ways of interpreting representation through an approach of design reconciliation.

EXPERIMENTAL ANALYSIS OF MULTINATIONAL GENETIC ALGORITHM AND ITS MODIFICATIONS

Context. Niching genetic algorithms are one of the most popular approaches to solve multimodal optimization problems. When classifying niching genetic algorithms it is possible to select algorithms explicitly analyzing topography of fitness function landscape; multinational genetic algorithm is one of the earliest examples of these algorithms. Objective. Development and analysis of the multinational genetic algorithm and its modifications to find all maxima of a multimodal function. Method. Experimental analysis of algorithms is carried out. Numerous runs of algorithms on well-known test problems are conducted and performance criteria are computed, namely, the percentage of convergence, real (global, local) and fake peak ratios; note that peak rations are computed only in case of algorithm convergence. Results. Software implementation of a multinational genetic algorithm has been developed and experimental tuning of its parameters has been carried out. Two modifications of hill-valley function used for determining the relative position of individuals have been proposed. Experimental analysis of the multinational genetic algorithm with classic hill-valley function and with its modifications has been carried out. Conclusions. The scientific novelty of the study is that hill-valley function modifications producing less number of wrong identifications of basins of attraction in comparison with classic hill-valley function are proposed. Using these modifications yields to performance improvements of the multinational genetic algorithm for a number of test functions; for other test functions improvement of the quality criteria is accompanied by the decrease of the convergence percentage. In general, the convergence percentage and the quality criterion values demonstrated by the algorithm studied are insufficient for practical use in comparison with other known algorithms. At the same time using modified hill-valley functions as a post-processing step for other niching algorithms seems to be a promising improvement of performance of these algorithms.

Assessment of comfort potential and prospects for environmental development of cities in steppe Russia using the index method

The paper describes the results of comfort potential assessment and prospects for development of urbanized geosystems in steppe Russia on the basis of constructed geoinformation index assessing potential for development of environmental comfort (CDPI). The index was calculated on various areas for technogenic geosystems, and the total area was represented by individual functional structures. The index was constructed as the ratio of existing and planned natural-anthropogenic components to the areas suitable for the expansion of green zones. For the first time, cartographic models were built, showing the spatial differentiation of urbanized geosystems. Index values, obtained for the studied objects (Simferopol and Rostov-on-Don), differ depending on planning structure development and topography of anthropogenic landscape. The index comfort indicators for the studied cities of Simferopol and Rostov-on-Don were characterized mainly by negative values. The highest index values were associated with urban areas in redevelopments of floodplain and terrace complexes, and also with small areas dispersed across local draw terraces.

Ecological Vegetation Restoration and Regeneration Technology of Abandoned Land for Remedying the Heavy Metals Polluted Soil

Urban industrial wasteland may have been affected by the pollution of toxic and harmful substances produced by the original production activities, and the original ecosystem has been severely damaged. Especially in abandoned mines, the soil is heavily polluted by heavy metals and ecological restoration is extremely difficult. Chinese urban industrial wasteland has the characteristics of a huge number and diverse types of damage to the ecological environment. The elements of landscape design should be scientifically laid out from the three aspects of visual communication, history and humanities, and landscape structure. At the same time, attention should be paid to the external expression and internal culture of the landscape. Connotation, restoration and regeneration of landscape structures, topography, vegetation, and water bodies to create a new urban landscape space that combines ecological protection, landscape appreciation, educational science, and urban memory. For this reason, the thesis expounds the vegetation reconstruction in the ecological restoration of various industrial wastelands, and mainly analyzes the three links of soil substrate improvement, plant species selection and plant planting technology.

A beneficial relationship: associated trees facilitate termite colonies (Macrotermes michaelseni) in Namibia

AbstractIn many tropical ecosystems, termites are important ecosystem engineers. Mound‐building termite species often contribute to topographical landscape heterogeneity, and the associated accumulation of soil moisture and nutrients affects the spatial distribution of plant communities. Plants that grow next to the termite mound are known to benefit from the provided nutrients and water storage. The other way around, protection against erosion and cooling effects on the microclimate of the mounds imposed by associated trees have been described. However, little is known regarding the influence of tree parameters and the long‐term effects on colony development. In an interval of 12 yr, we studied all Macrotermes michaelseni mounds occurring within one square kilometer of Namibian thornbush savanna in terms of morphology, life history, and associated plants, with a focus on the role of associated trees which grow directly adjacent to the termite mounds. Here, we present the results of a combined analysis of the character states recorded at the termite mound and the associated trees. More than 50% of all 345 recorded termite mounds were associated with a tree. Mounds with associated trees showed increased activity, growth, and height. Mound growth within the study period was correlated positively with the canopy coverage by the associated tree, while total mound heights were correlated non‐linear with medium canopy coverage of about 40%. Mounds with a tree covering the sun's average zenith (north) were taller, grew most within 12 yr, and were more likely to be active than those with no northern canopy coverage. Mounds associated with the evergreen Boscia albitrunca attained highest average height (195.06 ± 11.76 cm). We conclude that vital parameters like growth, size, and activity of the termite colonies are facilitated by shading associated trees. These benefits were shown to take significant effect within the span of 12 yr. This indicates a proper long‐term mutualism, not a loose alliance and not an obligative eu‐symbiosis. Therefore, we propose to use the term “partner tree” for trees associated with M. michaelseni mounds.

Site-Specific Determinants and Remains of Medieval City Fortifications as the Potential for Creating Urban Greenery Systems Based on the Example of Historical Towns of the Opole Voivodeship

The article discusses the natural and historic heritage of medieval towns in the Opole Silesia region in the context of their ability to take advantage of their potential for sustainable development, especially in tourism. The chosen environmental, urban, architectural, and landscape factors were compared through this aspect and subjected to a multidimensional comparative analysis. The research studies applied mostly archival materials, contemporary topographic maps, statistical data, and both landscape as well as urban field studies. As a result, the studies indicated that the natural conditions of the locations, the preservation level of the urban system along with its development trends, and the areas of the old fortifications with their accompanying greenery constitute these towns’ very value and identity. As they combine elements of nature and culture, they may serve as the basis for development of tourism, which is likely to contribute to the social and economic revitalization of the region itself. What may play a major role in the quest for sustainable development are the urban greenery systems to be designed based on former fortification areas, city greenery, and natural environmental resources, which have been integral elements of these towns over many past centuries.

Quaternary formations mapping in the region of Volta Grande do Rio Uruguai (Brazil)

Quaternary formations (detrital and weathered materials) are an important natural resource for different areas of scientific investigation, from understanding their relation to erosive processes and morphodynamic processes that create landforms or to understanding the history of the first human settlements (geoarcheology). Quaternary coverings can be formed in situ or be transported by external geologic agents. Regarding soils, Quaternary formations are related to landscape topography and are transformed according to the characteristics of this topography. Hence, classifying and mapping these soils is not always easy. The present article aims to map the Quaternary formations along a stretch of the Uruguay River basin known as Volta Grande (SC/RS-Brazil), by using topographic attributes derived from the SRTM GL1-Up Sampled digital elevation model, soil particle-size analysis, and a generated Multiresolution Index of Valley Bottom Flatness (MRVBF) index . The results of the analysis show that: (i) colluvium is the predominant Quaternary formation in the study area; (ii) there is a predominance of clay, corroborating previous studies of the region; (iii) the spatial distribution of the study area’s Quaternary formations reflect local slope dynamics based on morphology and topographic position; and, (iv) the existence of colluvium-alluvium on the Uruguay River’s banks indicates that slope attributes contributed to the pedogeomorphological dynamics of the study area and not only fluvial dynamics. Based on the results, the methodology applied in this study might be useful for pedogeomorphological studies, notably in the analysis and mapping of Quaternary formations, despite some of its limitations.

Dynamical landscape and multistability of a climate model.

We apply two independent data analysis methodologies to locate stable climate states in an intermediate complexity climate model and analyse their interplay. First, drawing from the theory of quasi-potentials, and viewing the state space as an energy landscape with valleys and mountain ridges, we infer the relative likelihood of the identified multistable climate states and investigate the most likely transition trajectories as well as the expected transition times between them. Second, harnessing techniques from data science, and specifically manifold learning, we characterize the data landscape of the simulation output to find climate states and basin boundaries within a fully agnostic and unsupervised framework. Both approaches show remarkable agreement, and reveal, apart from the well known warm and snowball earth states, a third intermediate stable state in one of the two versions of PLASIM, the climate model used in this study. The combination of our approaches allows to identify how the negative feedback of ocean heat transport and entropy production via the hydrological cycle drastically change the topography of the dynamical landscape of Earth’s climate.

THREE-DIMENSIONAL TOPOGRAPHIC MAPPING OF VERTICAL AND OVERHANGING SURFACES OF COASTAL CLIFFS USING UAV-BASED LIDAR DATASET

The availability of high-density LiDAR datasets, enabled by UAV-based airborne laser scanning, has allowed topographic mapping surveyors to see unprecedented details on the earth’s surface. One of the problems faced in large-scale topographic mapping is generating proper three-dimensional contour lines for vertical cliffs, recesses, and overhangs, especially when the surface is covered by vegetation, which is quite common in the tropical area. This paper showcases the practical application of the LiDAR survey using an unmanned aerial vehicle and ground point classification process using the Simple Morphological Filter (SMRF) algorithm to produce high-fidelity, three-dimensional digital contour maps of coastal cliffs. By rotating the LiDAR dataset before the classification process to minimize overlapping surfaces, the entire dataset can be simulated as a 2.5-D surface. Therefore, the SMRF algorithm can be executed to classify all ground points on the cliff surface, including the overhangs and recesses. The resulting ground surface derived from this classification process provided a sufficient approximation of the real-world surface in overhanging cliffs and recesses while maintaining the conventional way to convey local landscape topography through three-dimensional contour lines.

Global Free-Energy Landscapes as a Smoothly Joined Collection of Local Maps.

Enhanced sampling techniques have become an essential tool in computational chemistry and physics, where they are applied to sample activated processes that occur on a time scale that is inaccessible to conventional simulations. Despite their popularity, it is well known that they have constraints that hinder their application to complex problems. The core issue lies in the need to describe the system using a small number of collective variables (CVs). Any slow degree of freedom that is not properly described by the chosen CVs will hinder sampling efficiency. However, the exploration of configuration space is also hampered by including variables that are not relevant for the activated process under study. This paper presents the Adaptive Topography of Landscape for Accelerated Sampling (ATLAS), a new biasing method capable of working with many CVs. The root idea of ATLAS is to apply a divide-and-conquer strategy, where the high-dimensional CVs space is divided into basins, each of which is described by an automatically determined, low-dimensional set of variables. A well-tempered metadynamics-like bias is constructed as a function of these local variables. Indicator functions associated with the basins switch on and off the local biases so that the sampling is performed on a collection of low-dimensional CV spaces that are smoothly combined to generate an effectively high-dimensional bias. The unbiased Boltzmann distribution is recovered through reweighing, making the evaluation of conformational and thermodynamic properties straightforward. The decomposition of the free-energy landscape in local basins can be updated iteratively as the simulation discovers new (meta)stable states.

Localization in the Crowd with Topological Constraints

We address the problem of crowd localization, i.e., the prediction of dots corresponding to people in a crowded scene. Due to various challenges, a localization method is prone to spatial semantic errors, i.e., predicting multiple dots within a same person or collapsing multiple dots in a cluttered region. We propose a topological approach targeting these semantic errors. We introduce a topological constraint that teaches the model to reason about the spatial arrangement of dots. To enforce this constraint, we define a persistence loss based on the theory of persistent homology. The loss compares the topographic landscape of the likelihood map and the topology of the ground truth. Topological reasoning improves the quality of the localization algorithm especially near cluttered regions. On multiple public benchmarks, our method outperforms previous localization methods. Additionally, we demonstrate the potential of our method in improving the performance in the crowd counting task.

Topographic Landscape and Site Conditions of the Songjeong-dong Site, in Donghae

Topographic Landscape and Site Conditions of the Songjeong-dong Site, in Donghae

Countrywide mapping of trees outside forests based on remote sensing data in Switzerland

Although trees growing outside forests are less perceived in relation to those inside forests, they are also valuable and serve various functions. The biophysical thresholds of Trees Outside Forests (TOF) were recently defined and standardised by the Global Forest Resources Assessments of the United Nations Food and Agricultural Organization (UNFAO-FRA). With these definitions, standardised mapping of TOF resources became feasible at the national and international level. Here, we aimed to fill the spatial information gap of TOF resources at the national scale with an automated mapping approach based on the UNFAO-FRA definition. The approach was carried out in ArcGIS using adapted UNFAO-FRA biophysical thresholds with routinely acquired countrywide remote sensing data for the whole of Switzerland: a Vegetation Height Model (VHM), a Topographic Landscape Model (TLM Regio) land cover map, and a Forest Mask. Results were validated using stereo-image interpretation data of the Swiss National Forest Inventory (NFI), which verified 95%, 55% and 75% of overall, producer’s and user’s accuracy, respectively. Of the five forest production regions in Switzerland, the highest accuracy was achieved in the Central Plateau and the lowest in the Alps, with accuracy generally decreasing with increasing elevation. Omission and commission errors were highly correlated with the vertical and horizontal accuracy of the VHM, and the applied biophysical thresholds caused both types of error. The final TOF map produced with our approach is at the countrywide scale, is superior to existing TOF information, meets UNFAO-FRA management and reporting needs, and enables the derivation of TOF’s biomass, carbon sequestration potential and species distribution for the whole country.

Feeling Apollo: Sensory Engagement in the Sanctuary of Apollo at Klaros

This article explores the interplay between body and materiality in the ancient oracular Sanctuary of Apollo at Klaros. Drawing upon sensory archaeology and classical studies, the article moves beyond the static paradigm of city-as-map in order to discover the sensory experience of an ambulant body within the sanctuary. In this way, the article suggests that a visitor’s experience in Klaros was intensely sensorial. Sensory engagement began with the evocative topography of the natural landscape; continued along the via sacra with sights, smells, and sounds; and culminated in oracular consultation in the temple. Movement through the sanctuary served as a form of “circumabulatory knowing” in which the nature of Apollo was shaped by felt encounters within the sanctuary.

항공사진 및 퇴적물 분석을 통한 순천 동천하구의 지표경관 변화 및 퇴적환경 연구

In this study, we analyzed the changes in the topographical landscape and the sedimentary environment to evaluate the ecological value of the Dongcheon Estuary and protect the wetland, and presented the conservation management method of the Dongcheon Estuary. Based on the result of topographical landscape analysis, agricultural land tended to decrease continuously, and artificial structures gradually increased. Moreover, in sediment analysis, the Dongcheon Estuary showed both the characteristics of river sediments and coastal sediments, and in some areas problems such as acidification and nutritional imbalance appeared. Therefore, in order to protect and manage the Dongcheon Estuary with high ecological value, it is necessary to limit the development around micro topography and minimize the artificial damage in the Dongcheon Estuary. In addition, efforts such as securing facilities for reducing pollutants and freshwater wetlands for pollutants, that flow in from nonpoint pollutants are required.