Academic literature on the topic 'Topographic surveys. eng'
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Journal articles on the topic "Topographic surveys. eng"
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Xie, Hui, Haoran Wang, Yayi Yang, et al. "Analysis of Underwater Topographic Survey of Stilling Basin Based on Unmanned Survey System." Advances in Materials Science and Engineering 2021 (April 1, 2021): 1–15. http://dx.doi.org/10.1155/2021/5514165.
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The combination of Global Positioning System-Real Time Kinematic (GPS-RTK) and depth sounder is an important technical method of modern underwater topographic survey. In this paper, the combined technology was integrated with unmanned surface vehicle (USV) technology to construct an unmanned survey system suitable for underwater topographic survey in stilling basin, and it was applied to survey the underwater topography of the stilling basin of Tingzikou hydrojunction project. Based on the surveying and mapping data and 3D model, the trend of elevation change of the stilling basin including apron, end sill, antiscour section, and river convergence section was analyzed. The results show that, for the surface outlet stilling basin of Tingzikou, after flood, the structure is complete, the boundaries are clear, the water quality is good, and there is little sediment on the surface of apron from overflow dam section to end sill. Furthermore, no obvious sediment or structural abnormality has been found in the still basin. Affected by the bedrock and cofferdam cobble gravel sediment, the elevation of the antiscour section and the downstream convergence section of the surface outlet stilling basin increased significantly. For the bottom outlet stilling basin of Tingzikou, there is large sediment within a range of 20 m∼40 m from the bottom sill and the maximum height of it reaches 2.04 m, while there is no obvious sediment or structural abnormality in the remaining region of basin. The critical sedimentation height can effectively judge the safety grade of the sedimentation height in stilling basin and provide a reliable support for assessing the overall safety of stilling basin. The application of unmanned survey technology improves the accuracy and timeliness of underwater topography and sedimentation distribution of stilling basin, which has significant application research value and promotion significance.
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Vieira, Gonçalo Teles, Miguel Ramos, and Jorge Gárate. "Detailed geomorphological mapping with Kinematic GPS. Examples from Livingston Island, Antarctic." Estudos do Quaternário / Quaternary Studies, no. 4 (December 26, 2001): 35–42. http://dx.doi.org/10.30893/eq.v0i4.35.
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The detailed geomorphological mapping of landforms and deposits is widespread in Quaternary geomorphology studies. It consists on the precise representation of the spatial position of geomorphological information and their characterization (e.g. topography, hydrology, morphometry, morphography, morphogenesis,morphochronology and morphodynamics) in large-scale maps (usually 1:5,000 to 1:25,000).The data is collectcd using both remote sensing (aerial photo interpretation, satellite images, etc.) and detailed field surveys. However, in areas without topographic maps, or where the scale of the existing is too small, it becomes very difficult, or even impossible to make a detailed geomorphological survey. But even in areas with good topographic data, the precise location of small or very irregular landforms and deposits is frequently difficult. The recent development of high precision GPS (Global Positioning System) allows the cartographic produclion with an accuracy that could only be achieved using traditional geodetic surveys. The main advantage is the much raster working procedure and direct data storage in a digital format. The later can easily be integrated in a Geographical lnlormation System. The installation of a Kynematic GPS in the Spanish Antartic Station (Livingston Island, South Shetlands) in the Austral summer of 1999-2000, made its use possible in the framework of the geomorphological survey that was being conducted at lhe time. ln this paper the application of the Kynematic GPS system is explained and two examples of detailed geomorphological maps at the scale 1:5,000 produced using this technique are presented.
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Giannoulaki, Marianna, Athanassios Machias, Constantin Koutsikopoulos, and Stylianos Somarakis. "The effect of coastal topography on the spatial structure of anchovy and sardine." ICES Journal of Marine Science 63, no. 4 (2006): 650–62. http://dx.doi.org/10.1016/j.icesjms.2005.10.017.
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Abstract Acoustic-survey data from 1995 to 2004 (six acoustic surveys in summer and two in winter) in the Aegean and Ionian Seas (eastern Mediterranean Sea) were analysed to investigate the spatial organization of European anchovy and European sardine populations. The potential effect of certain topographic characteristics (e.g. area, bottom depth, and the degree of land enclosure) on the spatial structure of the fish was studied in different geographic subareas (i.e. how topography affects the organization of fish into clusters of schools). Parameters calculated by geostatistical techniques were used as descriptors of the spatial organization. The results indicate the significant effect of area and land enclosure on the spatial structures of both species, suggesting that environmental spatial heterogeneity attributable to coastal topography affected the way fish schools were organized into aggregations. In summer, the spatial structure of sardine was more heterogeneous in subareas with increased land enclosure, whereas the spatial structure of anchovy was not significantly related to any of the area characteristics examined. In winter, the spatial structure of both species was more heterogeneous in subareas with increased enclosure and in small rather than larger subareas. The findings are discussed in terms of the species' response to their environment.
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Hochmair, Hartwig, and Adam Benjamin. "An Introduction to USGS Topo Maps." EDIS 2021, no. 1 (2021): 7. http://dx.doi.org/10.32473/edis-fr432-2021.
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Topographic maps provide both a detailed and accurate representation of cultural and natural features on the ground and a quantitative representation of relief, usually using contour lines. They can be used to address spatial questions in disciplines related to natural resources, hydrology, forestry, agriculture, or ecology. In 1879, the United States Geological Survey began to map the topography of the United States, producing new map versions of each area at semi-regular time intervals. US Topo maps are the current generation of USGS topographic maps. Unlike traditional topographic maps, the US Topo product is automatically generated from national map databases with topographic maps and produced every three years for all 48 of the contiguous United States, Hawaii, and the United States territories. They are published as freely available geospatial PDF documents that facilitate coordinate readings and spatial measurements (e.g. distance, area) through built-in georeferencing technology. This 7-page fact sheet written by Hartwig H. Hochmair and Adam R. Benjamin and published by the UF/IFAS School of Forest Resources and Conservation focuses on US Topo quadrangle download procedures and layer structure. https://edis.ifas.ufl.edu/fr432
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Coviello, Velio, Joshua I. Theule, Stefano Crema, et al. "Combining Instrumental Monitoring and High-Resolution Topography for Estimating Sediment Yield in a Debris-Flow Catchment." Environmental and Engineering Geoscience 27, no. 1 (2020): 95–111. http://dx.doi.org/10.2113/eeg-d-20-00025.
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ABSTRACT In mountain basins, long-term instrumental monitoring coupled with high-resolution topographic surveys can provide important information on sediment yield. The Gadria catchment, located in the eastern Italian Alps, typically features several low-magnitude flood episodes and a few debris-flow events per year, from late spring to late summer. Beginning in 2011, sensors devoted to debris-flow detection (geophones, video cameras, flow stage sensors) were installed along the main channel, upstream of a retention basin. In case of debris flows, high-resolution topographical surveys of the retention basin are carried out multiple times per year. Rainfall is measured in the lower part of the catchment and at the headwaters, while passive integrated transponder tracing of bedload was performed in the main channel during spring and summer 2014. In this work, we present the reconstruction of the sediment dynamics at the catchment scale from 2011 to 2017. Results show that (i) coarse sediment yield is dominated by the few debris flows occurring per year; (ii) debris-flow volume estimations may be significantly different—up to 30 percent lower—when performed through a digital elevation model of difference analysis, compared to the time-integration of the debris-flow discharge estimates; (iii) using this latter method, the volumes are affected by significant uncertainties, particularly for small values of flow depth; and (iv) rainfall analysis permits us to characterize debris-flow initiation but also highlights difficulties in discriminating triggering from non-triggering rainstorms if based on rainfall duration and intensity only.
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Duffy, James, Jamie Shutler, Matthew Witt, Leon DeBell, and Karen Anderson. "Tracking Fine-Scale Structural Changes in Coastal Dune Morphology Using Kite Aerial Photography and Uncertainty-Assessed Structure-from-Motion Photogrammetry." Remote Sensing 10, no. 9 (2018): 1494. http://dx.doi.org/10.3390/rs10091494.
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Coastal dunes are globally-distributed dynamic ecosystems that occur at the land-sea interface. They are sensitive to disturbance both from natural forces and anthropogenic stressors, and therefore require regular monitoring to track changes in their form and function ultimately informing management decisions. Existing techniques employing satellite or airborne data lack the temporal or spatial resolution to resolve fine-scale changes in these environments, both temporally and spatially whilst fine-scale in-situ monitoring (e.g., terrestrial laser scanning) can be costly and is therefore confined to relatively small areas. The rise of proximal sensing-based Structure-from-Motion Multi-View Stereo (SfM-MVS) photogrammetric techniques for land surface surveying offers an alternative, scale-appropriate method for spatially distributed surveying of dune systems. Here we present the results of an inter- and intra-annual experiment which utilised a low-cost and highly portable kite aerial photography (KAP) and SfM-MVS workflow to track sub-decimetre spatial scale changes in dune morphology over timescales of between 3 and 12 months. We also compare KAP and drone surveys undertaken at near-coincident times of the same dune system to test the KAP reproducibility. Using a Monte Carlo based change detection approach (Multiscale Model to Model Cloud Comparison (M3C2)) which quantifies and accounts for survey uncertainty, we show that the KAP-based survey technique, whilst exhibiting higher x, y, z uncertainties than the equivalent drone methodology, is capable of delivering data describing dune system topographical change. Significant change (according to M3C2); both positive (accretion) and negative (erosion) was detected across 3, 6 and 12 months timescales with the majority of change detected below 500 mm. Significant topographic changes as small as ~20 mm were detected between surveys. We demonstrate that portable, low-cost consumer-grade KAP survey techniques, which have been employed for decades for hobbyist aerial photography, can now deliver science-grade data, and we argue that kites are well-suited to coastal survey where winds and sediment might otherwise impede surveys by other proximal sensing platforms, such as drones.
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Smith, M. W., J. L. Carrivick, and D. J. Quincey. "Structure from motion photogrammetry in physical geography." Progress in Physical Geography: Earth and Environment 40, no. 2 (2015): 247–75. http://dx.doi.org/10.1177/0309133315615805.
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Accurate, precise and rapid acquisition of topographic data is fundamental to many sub-disciplines of physical geography. Technological developments over the past few decades have made fully distributed data sets of centimetric resolution and accuracy commonplace, yet the emergence of Structure from Motion (SfM) with Multi-View Stereo (MVS) in recent years has revolutionised three-dimensional topographic surveys in physical geography by democratising data collection and processing. SfM-MVS originates from the fields of computer vision and photogrammetry, requires minimal expensive equipment or specialist expertise and, under certain conditions, can produce point clouds of comparable quality to existing survey methods (e.g. Terrestrial Laser Scanning). Consequently, applications of SfM-MVS in physical geography have multiplied rapidly. There are many practical options available to physical geographers when planning a SfM-MVS survey (e.g. platforms, cameras, software), yet, many SfM-MVS end-users are uncertain as to the errors associated with each choice and, perhaps most fundamentally, the processes actually taking place as part of the SfM-MVS workflow. This paper details the typical workflow applied by SfM-MVS software packages, reviews practical details of implementing SfM-MVS, combines existing validation studies to assess practically achievable data quality and reviews the range of applications of SfM-MVS in physical geography. The flexibility of the SfM-MVS approach complicates attempts to validate SfM-MVS robustly as each individual validation study will use a different approach (e.g. platform, camera, georeferencing method, etc.). We highlight the need for greater transparency in SfM-MVS processing and enhanced ability to adjust parameters that determine survey quality. Looking forwards, future prospects of SfM-MVS in physical geography are identified through discussion of more recent developments in the fields of image analysis and computer vision.
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Honrado, J., J. Vicente, A. Lomba, et al. "Fine-scale patterns of vegetation assembly in the monitoring of changes in coastal sand-dune landscapes." Web Ecology 10, no. 1 (2010): 1–14. http://dx.doi.org/10.5194/we-10-1-2010.
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Abstract. Understanding dune ecosystem responses to multi-scale environmental changes can provide the framework for reliable forecasts and cost-efficient protocols for detecting shifts in prevailing coastal dynamics. Based on the hypothesis that stress and disturbance interact as primary community controls in coastal dunes, we studied the fine-scale floristic assembly of foredune vegetation, in its relation to topography, along regional and local environmental gradients in the 200 km long coastline of northern Portugal, encompassing a major biogeographic transition in western Europe. Thirty topographic profiles perpendicular to the shoreline were recorded at ten sites along the regional climate gradient, and vegetation was sampled by recording the frequency of plant species along those profiles. Quantitative topographic attributes of vegetated dune profiles (e.g. length or height) exhibited wide variations relatable to differences in prevailing coastal dynamics. Metrics of taxonomic diversity (e.g. total species richness and its additive beta component) and of the functional composition of vegetation were highly correlated to attributes of dune topography. Under transgressive dynamics, vegetation profiles have fewer species, increased dominance, lower turnover rates, and lower total vegetation cover. These changes may drive a decrease in structural and functional diversity, with important consequences for resistance, resilience and other ecosystem properties. Moreover, differences in both vegetation assembly (in meta-stable dunes) and response to increased disturbance (in eroding dunes) between distinct biogeographic contexts highlight a possible decline in facilitation efficiency under extreme physical stress (i.e. under Mediterranean climate) and support the significance of functional approaches in the study of local ecosystem responses to disturbance along regional gradients. Our results strongly suggest that assessing fine-scale community assembly can provide insights on the relation between dune vegetation, environmental filters and ecosystem processes. A combination of cost-efficient indicators from dune topography and vegetation is thus suggested as a promising approach to survey, forecast and monitor changes in coastal dune ecosystems.
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Manfreda, Salvatore, Petr Dvorak, Jana Mullerova, et al. "Assessing the Accuracy of Digital Surface Models Derived from Optical Imagery Acquired with Unmanned Aerial Systems." Drones 3, no. 1 (2019): 15. http://dx.doi.org/10.3390/drones3010015.
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Small unmanned aerial systems (UASs) equipped with an optical camera are a cost-effective strategy for topographic surveys. These low-cost UASs can provide useful information for three-dimensional (3D) reconstruction even if they are equipped with a low-quality navigation system. To ensure the production of high-quality topographic models, careful consideration of the flight mode and proper distribution of ground control points are required. To this end, a commercial UAS was adopted to monitor a small earthen dam using different combinations of flight configurations and by adopting a variable number of ground control points (GCPs). The results highlight that optimization of both the choice and combination of flight plans can reduce the relative error of the 3D model to within two meters without the need to include GCPs. However, the use of GCPs greatly improved the quality of the topographic survey, reducing error to the order of a few centimeters. The combined use of images extracted from two flights, one with a camera mounted at nadir and the second with a 20° angle, was found to be beneficial for increasing the overall accuracy of the 3D model and especially the vertical precision.
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Hodgkins, Richard, Richard Cooper, Jemma Wadham, and Martyn Tranter. "Interannual variability in the spatial distribution of winter accumulation at a high-Arctic glacier (Finsterwalderbreen, Svalbard), and its relationship with topography." Annals of Glaciology 42 (2005): 243–48. http://dx.doi.org/10.3189/172756405781812718.
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AbstractGlacier mass balance and hydrology are strongly influenced by the distribution of snow accumulation at the start of the melt season. Two successive end-of-winter snow-cover surveys at Finsterwalderbreen, Svalbard, are here used to investigate the interannual variability in the spatial distribution of accumulation, and its relationship with topography. 40–62% of the variance in snow depth was not determined by elevation (assessed by linear regression of snow depth on surface elevation), which could not therefore necessarily be used as a sole predictor of the spatial distribution of accumulation here. Principal components (PC) analysis of the topographic variables elevation, slope, north–south and east–west aspects shows that only two of six PCs, determined for 2years’ sampling locations, had maximum loadings on altitude; aspect was more important, with maximum loadings on four PCs. Hierarchical cluster analysis was then applied to these PCs: significant correlations with accumulation in each of two terrain clusters were given by (1) elevation and slope, (2) east–west aspect only (1999); (1) elevation only, (2) no significant correlations (2000). There is strong interannual variability not only in the magnitude of winter accumulation (0.41 mw.e. in 1999, 0.58 mw.e. in 2000), but also in its spatial distribution, and its relationship with topography.
Dissertations / Theses on the topic "Topographic surveys. eng"
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Itame, Otávio Yassuo 1956. "Avaliação do posicionamento plano-altimétrico com receptor gps em diferentes tipos de uso do solo /." Botucatu : [s.n.], 2008. http://hdl.handle.net/11449/101877.
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Orientador: Zacarias Xavier de Barros<br>Banca: José Milton Arana<br>Banca: Osmar Delmanto Junior<br>Banca: Lincoln Gering Cardoso<br>Banca: Vilmar Antonio Rodrigues<br>Resumo: Neste trabalho, foram realizados levantamentos topográficos para a avaliação do efeito da cobertura vegetal, na recepção de sinais GPS, para obtenção de posicionamento tri-dimensional, considerando os estudos realizados em diferentes tipos de uso do solo. Vértices foram implantados em diferentes tipos de uso do solo; em área com pastagem, com plantação de seringueiras e com eucaliptos, e as suas posições determinadas com estação total, nivelamento geométrico e com receptores GPS. Na avaliação do posicionamento altimétrico adotou-se como valores de referência os desníveis determinados com o nivelamento geométrico para avaliação dos dados obtidos com receptores GPS. As coordenadas planimétricas obtidas com receptores GPS foram analisadas utilizando-se com valores de referência os dados obtidos com a estação total. No levantamento topográfico com estação total foram adotadas as prescrições estabelecidas nas Normas da Associação Brasileira de Normas Técnicas (ABNT) NBR 13.133, Execução de Levantamentos Topográficos, para poligonais do tipo IVP. Foi realizada a análise de exatidão e de precisão do posicionamento tridimensional, adotando como padrão a NBR 13133 da ABNT para a classe do levantamento executado. Para aplicações do GPS na altimetria há necessidade do conhecimento da ondulação geoidal (N), que neste trabalho, para a sua determinação foram coletados dados com receptor na referência de nível (RN). Os resultados obtidos indicam que cuidados especiais devem ser tomados nos levantamentos com receptores GPS em áreas com cobetura vegetal, pois estas interferem na propagação das ondas eletromagnéticas provenientes dos satélites podendo inviabilizar o posicionamento.<br>In this work, topographic surveys were carried out in order to evaluate the effect of vegetal cover, on the reception of GPS signals, for 3D positioning, considering studies to be made in different types of land use. Points were set up on different types of land use, in areas containing grass, rubber trees and eucalyptus, which had their positions defined using a total station, geometric leveling and GPS receivers In the evaluation of height positioning it was adopted as reference values the height differences determined by geometric levelling in order to evaluate data obtained through GPS receivers. Planimetric coordinates obtained by using GPS receivers were analysed using as reference values the data obtained using a total station. During the topographic survey using a total station the recommendations set up by the Brazilian Association for Technical Rules (ABNT) NBR 13.133, regarding the execution of topographic surveys, for transverses of type IVP. Accuracy and precision analysis was made on the 3D positioning, also considering ABNT NBR 13.133, for the class of topographic survey which was carried out. In order to apply GPS on height positiong it is necessary to know the geoidal ondulation (N) and, in this work, N was computed based upon data acquired employing receivers at the level reference (RN). The results obtained indicate that special care must be taken during the surveys carried out with the use of GPS receivers on areas with vegetal cover, because it causes interference in the propagation of electromagnetic waves from the satellite which can even make the positioning become unviable.<br>Doutor
Books on the topic "Topographic surveys. eng"
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Congendo, Marco, and Fernando H. Lopes da Silva. Event-Related Potentials. Edited by Donald L. Schomer and Fernando H. Lopes da Silva. Oxford University Press, 2017. http://dx.doi.org/10.1093/med/9780190228484.003.0039.
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Event-related potentials (ERPs) can be elicited by a variety of stimuli and events in diverse conditions. This chapter covers the methodology of analyzing and quantifying ERPs in general. Basic models (additive, phase modulation and resetting, potential asymmetry) that account for the generation of ERPs are discussed. The principles and requirements of ensemble time averaging are presented, along with several univariate and multivariate methods that have been proposed to improve the averaging procedure: wavelet decomposition and denoising, spatial, temporal and spatio-temporal filtering. We emphasize basic concepts of principal component analysis, common spatial pattern, and blind source separation, including independent component analysis. We cover practical questions related to the averaging procedure: overlapping ERPs, correcting inter-sweep latency and amplitude variability, alternative averaging methods (e.g., median), and estimation of ERP onset. Some specific aspects of ERP analysis in the frequency domain are surveyed, along with topographic analysis, statistical testing, and classification methods.
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Jung, Reinhard, ed. Punta di Zambrone I. Verlag der Österreichischen Akademie der Wissenschaften, 2021. http://dx.doi.org/10.1553/978oeaw86151.
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This monograph presents a significant portion of the scientific results of the archaeological excavations at the Bronze Age settlement site of Punta di Zambrone on the Tyrrhenian coast of Calabria (southern Italy). These excavations were conducted from 2011 to 2013 in an Italian-Austrian cooperation. The book is the first in a series dedicated to the final publication of those excavations and focuses on the later part of the settlement history (13th–12th cent. BCE). Major topics include the topography of the site (including a harbour bay), its chronology, investigations into the economic basis of the Bronze Age society and its local, regional and interregional interactions. The new data from Punta di Zambrone are evaluated in comparison with new research results from coeval sites in Italy and Greece, which forms the basis for a historical contextualization of the settlement and thus contributes to the broader reconstruction of Mediterranean history at the end of the second millennium BCE. These coeval sites are presented by their excavators or investigators. The authors conducted geophysical and bathymetric surveys as well as underwater archaeological investigations, typological analyses of artefacts, a definition of the relative and absolute chronology, archaeobotanic and archaeozoological studies, aDNA analysis, Sr isotope analyses on human and animal teeth, chemical and Pb isotope analyses on metal artefacts, provenance analyses of pottery vessels, amber and stone artefacts (from Zambrone and other sites).
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Series, Michigan Historical Reprint. Report of the survey of the north end northwest lakes: By Capt. George G. Meade, being Appendix I of the Report of the chief topographical engineer, accompanying ... Annual report of the secretary of war, 1858. Scholarly Publishing Office, University of Michigan Library, 2006.
Find full textBook chapters on the topic "Topographic surveys. eng"
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Lamberth, Curt, and Jocelyne M. R. Hughes. "Physical Variables in Freshwater Ecosystems." In Freshwater Ecology and Conservation. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198766384.003.0006.
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We consider three categories of physical variables that can be measured for different freshwater ecosystems: (1) variables measured or described at the catchment or sub-catchment scale (e.g., bathymetry, depth, topography, geology); (2) those in or near to the water (e.g., temperature, turbidity, solar radiation); and (3) variables used to describe the substrate (e.g., particle size, mineral vs. peat). In this chapter we consider the practical aspects of undertaking a freshwater survey that includes measurement of physical variables; the approaches needed to undertake the survey; choosing a sampling strategy or protocol; practical tips on choice of measurement method or sensor, battery type, equipment calibration, resolution, accuracy, and links to literature providing further detail. The final section provides examples from a diversity of freshwaters where physical variables have been measured as part of an ecological survey, forming the evidence-base for management or conservation decisions.
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Paga, Jessica. "The Akropolis." In Building Democracy in Late Archaic Athens. Oxford University Press, 2020. http://dx.doi.org/10.1093/oso/9780190083571.003.0002.
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This chapter focuses on the buildings of the Athenian Akropolis. A brief survey of earlier building activity is provided in order to consider how the Akropolis looked at the time of the Kleisthenic reforms and to highlight some of the problems and controversies in the architectural material. The issue of the “H-Architecture” (the Bluebeard Temple or Hekatompedon) is fully considered, including the ongoing controversy regarding its appearance and location. An account of the Akropolis at the end of the sixth and beginning of the fifth centuries then follows. The chapter closes with two sections that place these buildings within their broader topographical and historical context, including a calculation of the financial cost of the Old Athena Temple and a suggestion for how it might have been funded.
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Niang, Cheikh Ahmadou Bamba, David Baratoux, Dina Pathé Diallo, et al. "Systematic survey of K, Th, and U signatures in airborne radiometric data from Australian meteorite impact structures: Possible causes of circular features and implications." In Large Meteorite Impacts and Planetary Evolution VI. Geological Society of America, 2021. http://dx.doi.org/10.1130/2021.2550(15).
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ABSTRACT Airborne radiometric (gamma-ray) data provide estimates of the concentrations of potassium (K), thorium (Th), and uranium (U) in soil, regolith, and bedrock. Radiometric data constitute an important source of geochemical information, commonly used in mineral exploration and for geological mapping of Earth and other planets. Airborne radiometric data have rarely been applied to the exploration and analyses of impact structures, in contrast with other conventional geophysical tools (e.g., gravimetry, magnetism, and seismic reflection/refraction). This work represents the first systematic survey of the K, Th, and U radiometric signatures of Australian impact structures, based on the continent-wide airborne radiometric coverage of Australia. We first formulated several hypotheses regarding the possible causes of formation of circular radiometric patterns associated with impact structures. Then, the radiometric signatures of 17 exposed impact structures in Australia were documented. Our observations confirmed the supposition that impact structures are commonly associated with circular radiometric patterns. We then selected the five structures with the most prominent circular radiometric patterns (Gosses Bluff, Lawn Hill, Acraman, Spider, and Shoemaker), and we discuss the possible origin of these anomalies. Based on these five case studies, we argue that such patterns result from either crustal deformation induced by the impact event and/or from postimpact superficial processes controlled by the crater topography. This work also suggests that airborne radiometric data may be useful, in combination with other geophysical tools, in the search for new possible impact structures.
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Clarke, John Hughes. "Present-Day Methods of Depth Measurement." In Continental Shelf Limits. Oxford University Press, 2000. http://dx.doi.org/10.1093/oso/9780195117820.003.0015.
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Bathymetric data are needed to derive the morphological criteria that define the extent of the juridical continental shelf. Two features in particular, the '"foot of slope" and the 2500-m contour, must be defined. The previous chapter considered historical methods of determining bathymetry. This chapter will cover the present day methods that can be used to better meet the need for accurate bathymetry. In order to satisfy the demands of UNCLOS, bathymetric data are required in depths ranging from about 200 m to more than 5000 m. Shallower depths, while useful for demonstrating the morphology of the physical continental shelf, do not bear any relevance to the delineation of juridical continental shelf boundaries, other than where they are required to establish the baseline. Alternate methods to derive bathymetry other than using sound are available. Those involving airborne electromagnetic methods (e.g., electromagnetic induction, red-green lasers, and inversion of sea surface radar images) are not capable of determining depths much in excess of 40 m. The only other method potentially useful for deriving deeper water bathymetry is through inversion of sea surface altimetry obtained from satellites. This will be discussed at the end of this chapter. The optimal method thus remains acoustic. The traditional approach has been to use single-beam echo sounders (see previous chapter). This chapter discusses the more modern '"swath" sonar techniques, which are becoming widely used. The great majority of historic bathymetry has been collected using the single-beam sounding approach. As discussed in chapter 9, this method has a number of limitations, three of the most critical of which are i. incomplete coverage; ii. uncertainty about the exact location of the first arrival of the acoustic pulse; and iii. distortion of short-wavelength topography. In order to achieve more complete coverage, better echo location, and higher spatial resolution, methods were devised to project acoustic energy both within narrower solid angles (figure 10.1) and while deriving this information over angular sectors extending further out from the side of the survey vessel. All the methods commonly applied involved scanning the seabed orthogonal to the ship heading. Sequential scans, accumulated as the ship progresses, form a corridor (or swath) of seabed information (figure 10.2).
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"Benthic Habitats and the Effects of Fishing." In Benthic Habitats and the Effects of Fishing, edited by R. A. Coggan, C. J. Smith, R. J. A. Atkinson, et al. American Fisheries Society, 2005. http://dx.doi.org/10.47886/9781888569605.ch22.
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Traditional methods for assessing the impact of towed demersal fishing gear are notoriously slow, taking years to report and imposing undesirable delays in the provision of scientific advice on which fisheries and environmental managers can act. There is a need to develop rapid methods for assessing trawl impacts. We evaluate and compare a suite of rapid methodologies covering a range of readily accessible technologies including: (1) Acoustic methods: sidescan sonar and bottom discriminating sonar (RoxAnn); (2) Visual methods: towed video sledge and ROV; (3) Faunal sampling (epibenthic megafauna): tissue damage, community analysis, population density, functional group composition; and (4) Sedimentology: granulometry, geotechnical properties and sediment profile imagery. These methods were applied to otter trawl fisheries in the Clyde Sea, Scotland and the Aegean Sea, Mediterranean, at sites representing a range of trawl impacts. Novel methods of analysis were developed for quantitative interpretation of sidescan and video records. The scientific effectiveness, cost effectiveness and operational constraints of the various methodologies are reviewed. We recommend suitable approaches to the rapid assessment of trawl impacts taking into consideration the variety of resources (such as time, equipment and budget) which may be available. Assessments should employ complementary methods that operate on different scales of resolution (eg. sidescan sonar with either faunal sampling or ROV). Site-specific factors, such as topography and substratum type, will influence choice of methods and survey design. These rapid methodologies can provide results in a matter of days or weeks rather than the months or years associated with traditional assessment methods.
Conference papers on the topic "Topographic surveys. eng"
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Carpiceci, Marco, and Fabio Colonnese. "Le mura di Leonardo. I rilievi del 1502." In FORTMED2020 - Defensive Architecture of the Mediterranean. Universitat Politàcnica de València, 2020. http://dx.doi.org/10.4995/fortmed2020.2020.11363.
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Leonardo’s Walls. Surveys in 1502In the summer of 1502, Cesare Borgia appointed Leonardo da Vinci for his engineering expertise. His assignment was specific and concerning with military architecture: he was expected to “see, measure and do good estimation”. The Codex L, a small notebook conserved in the Library of the Institute of France, show the results of the survey of the city walls of Cesena and Urbino. The technique Leonardo adopted consists in traversing rectilinear stretches, measuring their length by means of an instrument able to count his steps and establishing their orientation by means of a compass. At the end of the path, the data relative to the sides of a closed polygon are obtained, resulting the geometric plan of the walls. This practice is testified by some residual eidotypes provided with quotas and orientations. In some cases, only the lists of distances in numbers are present, but the analysis of the figures makes it possible to reconstruct the surveyed plans, as Nando De Toni pioneered many years ago. This study focuses on the tools and the urban survey technique used by Leonardo. The analysis of some sheets from the Codex L, contextualized with respect to the actual topography of the sites, allows to understand the correct sequence of the operations carried out first in the site and then at the drawing board. By means of specific digital reconstructions, it is therefore possible to study the instrumental and operational limits of this practice and, by comparing it with the current state, to reconstruct the entire defensive structure.
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Sakamoto, Ryo, Ryo Sakamoto, Satoquo Seino, Satoquo Seino, Hirokazu Suzaki, and Hirokazu Suzaki. "COASTAL ALTERATION AND CHANGES IN SHORELINE MORPHOLOGY DUE TO ARTIFICIAL STRUCTURES IN MIIRAKU TOWN ON FUKUE IS. IN THE GOTO ARCHIPELAGO." In Managing risks to coastal regions and communities in a changing world. Academus Publishing, 2017. http://dx.doi.org/10.21610/conferencearticle_58b4315256b56.
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A construction of breakwaters and other shoreline structures on part of a coast influences drift sand transport in the bay, and causes comprehensive topographic changes on the beach. This study investigated shoreline and coastal changes, taking as an example of Shiraragahama Beach in Miiraku on the northwestern end of Fukue Island, Nagasaki Prefecture (Kyushu, Japan). Miiraku, adjacent to Saikai National Park, appears in the revered 8th century poetry collection “Manyoshu” and served as a port for a ship taken by the Japanese envoy to China during the Tang Dynasty (618-709). Because of the recent development of breakwaters for a fishing harbor, the shore environments of this beach have changed significantly. In this study, the status of silt deposits and topographic changes on this beach arising from the construction of a harbor breakwater were evaluated by comparing aerial photographs taken in different years. Next, the changes in the shoreline visible from aerial photographs from 1947 to 2014 were analyzed. Lastly, the altitude of the beaches was measured using accurate survey methods. The following results were obtained: 1) coastal erosion made rock cliffs to fall off along the shore and deposited sand on this beach; 2) the more serious advances or retreats of the shoreline took place around shoreline structures; 3) sandbars and beach cliffs were formed.
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Sakamoto, Ryo, Ryo Sakamoto, Satoquo Seino, Satoquo Seino, Hirokazu Suzaki, and Hirokazu Suzaki. "COASTAL ALTERATION AND CHANGES IN SHORELINE MORPHOLOGY DUE TO ARTIFICIAL STRUCTURES IN MIIRAKU TOWN ON FUKUE IS. IN THE GOTO ARCHIPELAGO." In Managing risks to coastal regions and communities in a changing world. Academus Publishing, 2017. http://dx.doi.org/10.31519/conferencearticle_5b1b9405463da4.93038143.
Full textAbstract:
A construction of breakwaters and other shoreline structures on part of a coast influences drift sand transport in the bay, and causes comprehensive topographic changes on the beach. This study investigated shoreline and coastal changes, taking as an example of Shiraragahama Beach in Miiraku on the northwestern end of Fukue Island, Nagasaki Prefecture (Kyushu, Japan). Miiraku, adjacent to Saikai National Park, appears in the revered 8th century poetry collection “Manyoshu” and served as a port for a ship taken by the Japanese envoy to China during the Tang Dynasty (618-709). Because of the recent development of breakwaters for a fishing harbor, the shore environments of this beach have changed significantly. In this study, the status of silt deposits and topographic changes on this beach arising from the construction of a harbor breakwater were evaluated by comparing aerial photographs taken in different years. Next, the changes in the shoreline visible from aerial photographs from 1947 to 2014 were analyzed. Lastly, the altitude of the beaches was measured using accurate survey methods. The following results were obtained: 1) coastal erosion made rock cliffs to fall off along the shore and deposited sand on this beach; 2) the more serious advances or retreats of the shoreline took place around shoreline structures; 3) sandbars and beach cliffs were formed.
Reports on the topic "Topographic surveys. eng"
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Wells, Aaron, Tracy Christopherson, Gerald Frost, et al. Ecological land survey and soils inventory for Katmai National Park and Preserve, 2016–2017. National Park Service, 2021. http://dx.doi.org/10.36967/nrr-2287466.
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This study was conducted to inventory, classify, and map soils and vegetation within the ecosystems of Katmai National Park and Preserve (KATM) using an ecological land survey (ELS) approach. The ecosystem classes identified in the ELS effort were mapped across the park, using an archive of Geo-graphic Information System (GIS) and Remote Sensing (RS) datasets pertaining to land cover, topography, surficial geology, and glacial history. The description and mapping of the landform-vegetation-soil relationships identified in the ELS work provides tools to support the design and implementation of future field- and RS-based studies, facilitates further analysis and contextualization of existing data, and will help inform natural resource management decisions. We collected information on the geomorphic, topographic, hydrologic, pedologic, and vegetation characteristics of ecosystems using a dataset of 724 field plots, of which 407 were sampled by ABR, Inc.—Environmental Research and Services (ABR) staff in 2016–2017, and 317 were from existing, ancillary datasets. ABR field plots were located along transects that were selected using a gradient-direct sampling scheme (Austin and Heligers 1989) to collect data for the range of ecological conditions present within KATM, and to provide the data needed to interpret ecosystem and soils development. The field plot dataset encompassed all of the major environmental gradients and landscape histories present in KATM. Individual state-factors (e.g., soil pH, slope aspect) and other ecosystem components (e.g., geomorphic unit, vegetation species composition and structure) were measured or categorized using standard classification systems developed for Alaska. We described and analyzed the hierarchical relationships among the ecosystem components to classify 92 Plot Ecotypes (local-scale ecosystems) that best partitioned the variation in soils, vegetation, and disturbance properties observed at the field plots. From the 92 Plot Ecotypes, we developed classifications of Map Ecotypes and Disturbance Landscapes that could be mapped across the park. Additionally, using an existing surficial geology map for KATM, we developed a map of Generalized Soil Texture by aggregating similar surficial geology classes into a reduced set of classes representing the predominant soil textures in each. We then intersected the Ecotype map with the General-ized Soil Texture Map in a GIS and aggregated combinations of Map Ecotypes with similar soils to derive and map Soil Landscapes and Soil Great Groups. The classification of Great Groups captures information on the soil as a whole, as opposed to the subgroup classification which focuses on the properties of specific horizons (Soil Survey Staff 1999). Of the 724 plots included in the Ecotype analysis, sufficient soils data for classifying soil subgroups was available for 467 plots. Soils from 8 orders of soil taxonomy were encountered during the field sampling: Alfisols (<1% of the mapped area), Andisols (3%), Entisols (45%), Gelisols (<1%), Histosols (12%), Inceptisols (22%), Mollisols (<1%), and Spodosols (16%). Within these 8 Soil Orders, field plots corresponded to a total of 74 Soil Subgroups, the most common of which were Typic Cryaquents, Typic Cryorthents, Histic Cryaquepts, Vitrandic Cryorthents, and Typic Cryofluvents.
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Hunter, Fraser, and Martin Carruthers. Scotland: The Roman Presence. Society of Antiquaries of Scotland, 2012. http://dx.doi.org/10.9750/scarf.06.2012.104.
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The main recommendations of the panel report can be summarised under five key headings: Scotland in the Roman world: Research into Roman Scotland requires an appreciation of the wider frontier and Empire-wide perspectives, and Scottish projects must be integrated into these wider, international debates. The rich data set and chronological control that Scotland has to offer can be used to inform broader understandings of the impact of Rome. Changing worlds: Roman Scotland’s rich data set should be employed to contribute to wider theoretical perspectives on topics such as identity and ethnicity, and how these changed over time. What was the experience of daily life for the various peoples in Roman Scotland and how did interactions between incomers and local communities develop and change over the period in question, and, indeed, at and after its end? Frontier Life: Questions still remain regarding the disposition and chronology of forts and forces, as well as the logistics of sustaining and supplying an army of conquest and occupation. Sites must be viewed as part of a wider, interlocking set of landscapes, and the study of movement over land and by sea incorporated within this. The Antonine Wall provides a continuing focus of research which would benefit from more comparison with frontier structures and regimes in other areas. Multiple landscapes: Roman sites need to be seen in a broader landscape context, ‘looking beyond the fort’ and explored as nested and interlocking landscapes. This will allow exploration of frontier life and the changing worlds of the Roman period. To do justice to this resource requires two elements: o Development-control archaeology should look as standard at the hinterland of forts (up to c.1 km from the ‘core’), as sensitive areas and worthy of evaluation; examples such as Inveresk show the density of activity around such nodes. The interiors of camps should be extensively excavated as standard. o Integrated approaches to military landscapes are required, bringing in where appropriate topographical and aerial survey, LIDAR, geophysics, the use of stray and metal-detected finds, as well as fieldwalking and ultimately, excavation. The Legacy of Rome: How did the longer term influence of the Romans, and their legacy, influence the formation, nature and organisation of the Pictish and other emergent kingdoms?