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Xie, Hui, Haoran Wang, Yayi Yang, Yongcan Chen, Jun Yang, Shuang Wang, and Zhaowei Liu. "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 (January 1, 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 (January 26, 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, Massimo Arattano, Francesco Comiti, Marco Cavalli, Ana LucÍa, Pierpaolo Macconi, and Lorenzo Marchi. "Combining Instrumental Monitoring and High-Resolution Topography for Estimating Sediment Yield in a Debris-Flow Catchment." Environmental and Engineering Geoscience 27, no. 1 (December 2, 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 (September 18, 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 (November 26, 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, P. Alves, J. A. Macedo, R. Henriques, H. Granja, and F. B. Caldas. "Fine-scale patterns of vegetation assembly in the monitoring of changes in coastal sand-dune landscapes." Web Ecology 10, no. 1 (February 10, 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, Sorin Herban, Pietro Vuono, José Arranz Justel, and Matthew Perks. "Assessing the Accuracy of Digital Surface Models Derived from Optical Imagery Acquired with Unmanned Aerial Systems." Drones 3, no. 1 (January 30, 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.
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SAVVAIDIS, A., G. TSOKAS, P. TSOURLOS, G. VARGEMEZIS, A. CHRYSOSTOMOU, and P. CRYSOSTOMOU. "A geophysical survey in the archaeological site of Archontiko, Yannitsa." Bulletin of the Geological Society of Greece 34, no. 4 (January 1, 2001): 1379. http://dx.doi.org/10.12681/bgsg.17231.
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The ancient settlement of Archontiko is 4.5 km NW of ancient Pella in North Greece (Figure 1). The findings showed that the area was first occupied by the end of the Iron Age, i.e. 650-550 B.C. Also, showed that the topographic table of Archontiko was a major settlement of the Yannitsa province due to its concessive position by the main roads of Macedonia (Chrysostomou A. and Chrysostomou P., 1993). At the upper layers of the ruins, findings of the Roman and Byzantine times were also unearthed. The geophysical methods have been used in order to detect and map antiquities in various sites in Greece (e.g., Tsokas et al., 1994; 1995; Sawaidis et al., 1999). The resistivity mapping employing the twin probe array, the total magnetic field variations, the airborne photos and the Ground Probing Radar are the most popular methods in this respect. However, almost all geophysical methods can be used to tackle specific problems. From 1992 till 1994, many geophysical surveys were carried out in the area of Archontiko to collect mainly magnetic data. Resistivity measurements were also conducted in a small part of the area. The data presented in this study cover the northern side of the topographic table of Archontiko and they were collected during two campaigns during the summer of the years 1992 and 1993 (Figure 2).
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Cucchiaro, S., E. Maset, A. Fusiello, and F. Cazorzi. "4D-SFM PHOTOGRAMMETRY FOR MONITORING SEDIMENT DYNAMICS IN A DEBRIS-FLOW CATCHMENT: SOFTWARE TESTING AND RESULTS COMPARISON." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-2 (May 30, 2018): 281–88. http://dx.doi.org/10.5194/isprs-archives-xlii-2-281-2018.
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In recent years, the combination of Structure-from-Motion (SfM) algorithms and UAV-based aerial images has revolutionised 3D topographic surveys for natural environment monitoring, offering low-cost, fast and high quality data acquisition and processing. A continuous monitoring of the morphological changes through multi-temporal (4D) SfM surveys allows, e.g., to analyse the torrent dynamic also in complex topography environment like debris-flow catchments, provided that appropriate tools and procedures are employed in the data processing steps. In this work we test two different software packages (3DF Zephyr Aerial and Agisoft Photoscan) on a dataset composed of both UAV and terrestrial images acquired on a debris-flow reach (Moscardo torrent – North-eastern Italian Alps). Unlike other papers in the literature, we evaluate the results not only on the raw point clouds generated by the Structure-from- Motion and Multi-View Stereo algorithms, but also on the Digital Terrain Models (DTMs) created after post-processing. Outcomes show differences between the DTMs that can be considered irrelevant for the geomorphological phenomena under analysis. This study confirms that SfM photogrammetry can be a valuable tool for monitoring sediment dynamics, but accurate point cloud post-processing is required to reliably localize geomorphological changes.
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Thomas, M., R. W. Fitzpatrick, and G. S. Heinson. "Distribution and causes of intricate saline - sodic soil patterns in an upland South Australian hillslope." Soil Research 47, no. 3 (2009): 328. http://dx.doi.org/10.1071/sr07191.
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We describe a soil–landscape investigation conducted in a South Australian upland hillslope (128 ha) to understand the distribution and causes of saline–sodic soil patterns using convenient, ground-based geophysical surveys of the hillslope. These surveys included: (i) EM31 for deep (~6 m) apparent electrical conductivity (ECa) patterns, (ii) EM38 for shallow (>1.5 m) ECa patterns, and (iii) Bartington MS2-D loop sensor for surface volume magnetic susceptibility (κ) patterns. From these surveys we inferred hillslope distributions of: (i) deep (~6 m) concentrations of salinity associated with deep groundwater systems and deposits of magnetic gravels (dominated by maghemite and hematite) (EM31 sensor); (ii) shallow (<1.5 m) soil salinity (EM38 sensor); and (iii) preservation of pedogenic magnetic materials (e.g. maghemite and hematite) (MS2-D loop sensor). We also describe terrain analysis to locate near-surface hydropedological patterns using topographic wetness index. When combined in 3D geographic information system, strong visual matches were identified between patterns in: (i) geophysical surveys, (ii) terrain, and (iii) soil survey data, thus allowing integrated interpretations of soil–landscape pedogenic processes to be made on a whole-of-landscape basis. Such mechanistic interpretations of soil–landscape processes reveal and map intricate saline and sodic soil–regolith patterns and groundwater and fresh surface water flow paths that were not revealed during a previous traditional soil survey.
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Luppichini, Favalli, Isola, Nannipieri, Giannecchini, and Bini. "Influence of Topographic Resolution and Accuracy on Hydraulic Channel Flow Simulations: Case Study of the Versilia River (Italy)." Remote Sensing 11, no. 13 (July 9, 2019): 1630. http://dx.doi.org/10.3390/rs11131630.
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The Versilia plain, a well-known and populated tourist area in northwestern Tuscany, is historically subject to floods. The last hydrogeological disaster of 1996 resulted in 13 deaths and in loss worth hundreds of millions of euros. A valid management of the hydraulic and flooding risks of this territory is therefore mandatory. A 7.5 km-long stretch of the Versilia River was simulated in one-dimension using river cross-sections with the FLO-2D Basic model. Simulations of the channel flow and of its maximum flow rate under different input conditions highlight the key role of topography: uncertainties in the topography introduce much larger errors than the uncertainties in roughness. The best digital elevation model (DEM) available for the area, a 1-m light detection and ranging (LiDAR) DEM dating back to 2008–2010, does not reveal all the hydraulic structures (e.g., the 40 cm thick embankment walls), lowering the maximum flow rate to only 150 m3/s, much lower than the expected value of 400 m3/s. In order to improve the already existing input topography, three different possibilities were considered: (1) to add the embankment walls to the LiDAR data with a targeted Differential GPS (DGPS) survey, (2) to acquire the cross section profiles necessary for simulation with a targeted DGPS survey, and (3) to achieve a very high resolution topography using structure from motion techniques (SfM) from images acquired using an unmanned aerial vehicle (UAV). The simulations based on all these options deliver maximum flow rates in agreement with estimated values. Resampling of the 10 cm cell size SfM-DSM allowed us to investigate the influence of topographic resolution on hydraulic channel flow, demonstrating that a change in the resolution from 30 to 50 cm alone introduced a 10% loss in the maximum flow rate. UAV-SfM-derived DEMs are low cost, relatively fast, very accurate, and they allow for the monitoring of the channel morphology variations in real time and to keep the hydraulic models updated, thus providing an excellent tool for managing hydraulic and flooding risks.
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CAMEROTA, FILIPPO. "IL DISEGNO DEL TERRITORIO E LA DIFESA DELLO STATO." Nuncius 14, no. 2 (1999): 455–69. http://dx.doi.org/10.1163/182539199x00030.
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Abstracttitle SUMMARY /title The National Archive of Lucca holds an extensive collection of drawings that document a wide-ranging campaign of topographical surveys carried out between 1580 and 1583 for the purpose of tracing a detailed map of fortifications under the domain of the Republic of Lucca. The surveys lie chronologically between the map drawn by the military engineer Alessandro Resta in 1567 and the accurate chorography of the State of Lucca produced at the end of the same century by the Paduan cosmographer Giovanni Antonio Magini. Historical circumstances suggest that the surveys may be attributed to the military engineer Vincenzo Civitali, who had been hired during that period to superintend the State's fortifications along the border between the Duchy of Modena and the Grand Duchy of Tuscany. Apart from providing information on the Republic's cartographic and defense projects, these drawings provide firsthand documentation of the work of a 16th C. topographer, as well as revealing the strategy applied when locating measuring stations which often coincided with a signaling tower, the choice of measuring instruments most readily associated with the simple theodolite, and the adoption of a surveying methodology that consisted in measuring azimuths and distances according to the codified precepts of 16th C. treatise writers.
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Fraser, D., S. Sepehr, and E. Stefanakis. "A geospatial reference framework for a university campus: a case study for managing student surveyed topographic data." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XL-2 (November 11, 2014): 157–60. http://dx.doi.org/10.5194/isprsarchives-xl-2-157-2014.
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This presentation describes a geospatial reference framework for managing student surveyed topographic data of a university campus. This topographic data is collected annually by Geodesy and Geomatics Engineering (GGE) students at the University of New Brunswick (UNB) as part of the requirements for a UNB course. Examples of the type of features collected include: buildings, roads, sidewalks, walking paths, bike racks, parking lots and parking designation (e.g. accessibility parking). The applications and the information products built for managing this student surveyed topographic data can be viewed as a geospatial reference framework for this GGE survey camp.
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Beem, Lucas H., Duncan A. Young, Jamin S. Greenbaum, Donald D. Blankenship, Marie G. P. Cavitte, Jingxue Guo, and Sun Bo. "Aerogeophysical characterization of Titan Dome, East Antarctica, and potential as an ice core target." Cryosphere 15, no. 4 (April 8, 2021): 1719–30. http://dx.doi.org/10.5194/tc-15-1719-2021.
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Abstract. Based on sparse data, Titan Dome has been identified as having a higher probability of containing ice that would capture the middle Pleistocene transition (1.25 to 0.7 Ma). New aerogeophysical observations (radar and laser altimetry) collected over Titan Dome, located about 200 km from the South Pole within the East Antarctic Ice Sheet, were used to characterize the region (e.g., geometry, internal structure, bed reflectivity, and flow history) and assess its suitability as a paleoclimate ice core site. The radar coupled with an available ice core chronology enabled the tracing of dated internal reflecting horizons throughout the region, which also served as constraints on basal ice age modeling. The results of the survey revealed new basal topographic detail and better constrain the ice topographical location of Titan Dome, which differs between community datasets. Titan Dome is not expected to be relevant to the study of the middle Pleistocene transition due to a combination of past fast flow dynamics, the basal ice likely being too young, and the temporal resolution likely being too coarse if 1 Ma ice were to exist.
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Wei, Yanfei, Xinhua Tong, Gang Chen, Deqiang Liu, and Zhenfeng Han. "Remote Detection of Large-Area Crop Types: The Role of Plant Phenology and Topography." Agriculture 9, no. 7 (July 9, 2019): 150. http://dx.doi.org/10.3390/agriculture9070150.
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Sustainable agricultural practices necessitate accurate baseline data of crop types and their detailed spatial distribution. Compared with field surveys, remote sensing has demonstrated superior performance, offering spatially explicit crop distribution in a timely manner. Recent studies have taken advantage of remote sensing time series to capture the variation in plant phenology, inferring major crop types. However, such an approach was rarely used to extract detailed, multiple crop types spanning a large area, and the impact of topography has yet to be well analyzed in mountainous regions. This study aims to answer two questions in crop type extraction: (i) Is it feasible to accurately map multiple crop types over a large mountainous area with phenology-based modeling? (ii) What are the effects of topography in such modeling? To answer the questions, phenological metrics were extracted from MODIS (Moderate Resolution Imaging Spectroradiometer) satellite time series, and the random forests classifier was used to map 12 crop types in South China (236,700 km2), featuring a subtropical monsoon climate and high topographic variation. Our study revealed promising results using MODIS EVI (Enhanced Vegetation Index) and NDVI (Normalized Difference Vegetation Index) time series, although EVI outperformed NDVI (overall accuracy: 85% versus 81%). The spectral and temporal metrics of plant phenology significantly contributed to crop identification, where the spectral information exhibited greater importance. The increase of slope led to a decrease in model accuracy in general. However, uniformly distributed tree plantations (e.g., tea-oil camellia, gum, and tea trees) being cultivated on large slopes (>15 degrees) achieved accuracies greater than 80%.
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Tampubolon, W., and W. Reinhardt. "UAV Data Processing for Large Scale Topographical Mapping." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XL-5 (June 6, 2014): 565–72. http://dx.doi.org/10.5194/isprsarchives-xl-5-565-2014.
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Large scale topographical mapping in the third world countries is really a prominent challenge in geospatial industries nowadays. On one side the demand is significantly increasing while on the other hand it is constrained by limited budgets available for mapping projects. Since the advent of Act Nr.4/yr.2011 about Geospatial Information in Indonesia, large scale topographical mapping has been on high priority for supporting the nationwide development e.g. detail spatial planning. Usually large scale topographical mapping relies on conventional aerial survey campaigns in order to provide high resolution 3D geospatial data sources. Widely growing on a leisure hobby, aero models in form of the so-called Unmanned Aerial Vehicle (UAV) bring up alternative semi photogrammetric aerial data acquisition possibilities suitable for relatively small Area of Interest (AOI) i.e. <5,000 hectares. For detail spatial planning purposes in Indonesia this area size can be used as a mapping unit since it usually concentrates on the basis of sub district area (kecamatan) level. In this paper different camera and processing software systems will be further analyzed for identifying the best optimum UAV data acquisition campaign components in combination with the data processing scheme. The selected AOI is covering the cultural heritage of Borobudur Temple as one of the Seven Wonders of the World. A detailed accuracy assessment will be concentrated within the object feature of the temple at the first place. Feature compilation involving planimetric objects (2D) and digital terrain models (3D) will be integrated in order to provide Digital Elevation Models (DEM) as the main interest of the topographic mapping activity. By doing this research, incorporating the optimum amount of GCPs in the UAV photo data processing will increase the accuracy along with its high resolution in 5 cm Ground Sampling Distance (GSD). Finally this result will be used as the benchmark for alternative geospatial data acquisition in the future in which it can support national large scale topographical mapping program up to the 1:1.000 map scale.
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Cucchiaro, Sara, Daniel J. Fallu, He Zhang, Kevin Walsh, Kristof Van Oost, Antony G. Brown, and Paolo Tarolli. "Multiplatform-SfM and TLS Data Fusion for Monitoring Agricultural Terraces in Complex Topographic and Landcover Conditions." Remote Sensing 12, no. 12 (June 17, 2020): 1946. http://dx.doi.org/10.3390/rs12121946.
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Agricultural terraced landscapes, which are important historical heritage sites (e.g., UNESCO or Globally Important Agricultural Heritage Systems (GIAHS) sites) are under threat from increased soil degradation due to climate change and land abandonment. Remote sensing can assist in the assessment and monitoring of such cultural ecosystem services. However, due to the limitations imposed by rugged topography and the occurrence of vegetation, the application of a single high-resolution topography (HRT) technique is challenging in these particular agricultural environments. Therefore, data fusion of HRT techniques (terrestrial laser scanning (TLS) and aerial/terrestrial structure from motion (SfM)) was tested for the first time in this context (terraces), to the best of our knowledge, to overcome specific detection problems such as the complex topographic and landcover conditions of the terrace systems. SfM–TLS data fusion methodology was trialed in order to produce very high-resolution digital terrain models (DTMs) of two agricultural terrace areas, both characterized by the presence of vegetation that covers parts of the subvertical surfaces, complex morphology, and inaccessible areas. In the unreachable areas, it was necessary to find effective solutions to carry out HRT surveys; therefore, we tested the direct georeferencing (DG) method, exploiting onboard multifrequency GNSS receivers for unmanned aerial vehicles (UAVs) and postprocessing kinematic (PPK) data. The results showed that the fusion of data based on different methods and acquisition platforms is required to obtain accurate DTMs that reflect the real surface roughness of terrace systems without gaps in data. Moreover, in inaccessible or hazardous terrains, a combination of direct and indirect georeferencing was a useful solution to reduce the substantial inconvenience and cost of ground control point (GCP) placement. We show that in order to obtain a precise data fusion in these complex conditions, it is essential to utilize a complete and specific workflow. This workflow must incorporate all data merging issues and landcover condition problems, encompassing the survey planning step, the coregistration process, and the error analysis of the outputs. The high-resolution DTMs realized can provide a starting point for land degradation process assessment of these agriculture environments and supplies useful information to stakeholders for better management and protection of such important heritage landscapes.
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Williams, James H., Thomas M. Wilson, Nick Horspool, Ryan Paulik, Liam Wotherspoon, Emily M. Lane, and Matthew W. Hughes. "Assessing transportation vulnerability to tsunamis: utilising post-event field data from the 2011 Tōhoku tsunami, Japan, and the 2015 Illapel tsunami, Chile." Natural Hazards and Earth System Sciences 20, no. 2 (February 19, 2020): 451–70. http://dx.doi.org/10.5194/nhess-20-451-2020.
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Abstract. Transportation infrastructure is crucial to the operation of society, particularly during post-event response and recovery. Transportation assets, such as roads and bridges, can be exposed to tsunami impacts when near the coast. Using fragility functions in an impact assessment identifies potential tsunami effects to inform decisions on potential mitigation strategies. Such functions have not been available for transportation assets exposed to tsunami hazard in the past due to limited empirical datasets. This study provides a suite of observations on the influence of tsunami inundation depth, road-use type, culverts, inundation distance, debris and coastal topography. Fragility functions are developed for roads, considering inundation depth, road-use type, and coastal topography and, for bridges, considering only inundation depth above deck base height. Fragility functions are developed for roads and bridges through combined survey and remotely sensed data for the 2011 Tōhoku earthquake and tsunami, Japan, and using post-event field survey data from the 2015 Illapel earthquake and tsunami, Chile. The fragility functions show a trend of lower tsunami vulnerability (through lower probabilities of reaching or exceeding a given damage level) for road-use categories of potentially higher construction standards. The topographic setting is also shown to affect the vulnerability of transportation assets in a tsunami, with coastal plains seeing higher initial vulnerability in some instances (e.g. for state roads with up to 5 m inundation depth) but with coastal valleys (in some locations exceeding 30 m inundation depth) seeing higher asset vulnerability overall. This study represents the first peer-reviewed example of empirical road and bridge fragility functions that consider a range of damage levels. This suite of synthesised functions is applicable to a variety of exposure and attribute types for use in global tsunami impact assessments to inform resilience and mitigation strategies.
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Barrowman, Rachel C., Charlotte Francoz, Janet Hooper, Christine Rennie, and Gary Tompsett. "Chapel-sites on the Isle of Lewis: Results of the Lewis Coastal Chapel-sites Survey." Scottish Archaeological Internet Reports 88 (February 17, 2020): 1–134. http://dx.doi.org/10.9750/issn.2056-7421.2020.88.
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The Lewis Coastal Chapel-sites Survey undertook research and fieldwork, the latter between 2004 and 2008, to explore and record the known chapel-sites on the Isle of Lewis in the Western Isles of Scotland. There is a scarcity of surviving contemporary historical documentation relating to Lewis in the medieval period, but archaeology has great potential to further investigate these fascinating and diverse sites. Research linked together previous antiquarian and local historical research, with walkover survey and description of each site on the ground. This was followed by targeted topographic and geophysical surveys of particular sites. At the end of the project it was possible to assess the cultural and research potential of this remarkable group of sites, and to identify gaps where further work was needed. More than 40 sites were identified and the remains recorded at each site were varied, some associated with old settlements, or traditionally linked with other chapel-sites nearby, others alone and isolated. The chapels themselves ranged from upstanding buildings still used for worship, to low grassy banks only just discernible beneath the turf or unlocated and kept alive only in oral tradition. This publication reports on the results of the survey work with a brief conclusion of the main findings.
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Beregovoi, D. V., and M. G. Mustafin. "Automated method of а topographic plan creation based on survey from a drone." Geodesy and Cartography 939, no. 9 (October 20, 2018): 30–36. http://dx.doi.org/10.22389/0016-7126-2018-939-9-30-36.
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The authors show an automated method for performing the main stages of creating a topographic plan. The optimal number and location of the reference points for creation a digital terrain model using drones is determined. The necessary components of a multi-rotor helicopter are described. They are required for lifting the camera into the air and increasing the duration of the flight. On the basis of the research, a significant speed increase of the field work was achieved using effective satellite and linear-angular measurements for determination of the reference points’ coordinates and productive survey from anunmanned aerial vehicle. Algorithms forconstructing an orthophoto and a digital terrain model as well as automated filtering of the resulting dense point cloud for creating a digital surface model are presented. The high-accurate modification of the OBIA (Object-Based Image Analysis) algorithm for classification of ground objects is determined. At the end of the article, the algorithm for automated vectorization of the raster classification using the ArcGIS geoinformation software and converting of the received objects to convention for creating an electronic topographic plan is given.
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Marti, R., S. Gascoin, T. Houet, O. Ribière, D. Laffly, T. Condom, S. Monnier, et al. "Evolution of Ossoue Glacier (French Pyrenees) since the end of the Little Ice Age." Cryosphere Discussions 9, no. 2 (April 17, 2015): 2431–94. http://dx.doi.org/10.5194/tcd-9-2431-2015.
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Abstract. Long-term climate records are rare at high elevations in Southern Europe. Here, we reconstructed the evolution of Ossoue Glacier (42°46' N, 0.45 km2), located in the Pyrenees (3404 m a.s.l.), since the Little Ice Age (LIA). Glacier length, area, thickness and mass changes indicators were generated from historical datasets, topographic surveys, glaciological measurements (2001–2013), a GPR survey (2006) and stereoscopic satellite images (2013). The glacier has receded considerably since the end of the LIA, losing 40 % of its length and 60% of its area. Three periods of marked ice depletion can be identified: 1850–1890, 1928–1950 and 1983–2013, as well as two periods of stabilization or slightly growth: 1905–1928 and 1950–1983; these agree with climatic datasets (air temperature, precipitation, North Atlantic Oscillation, Atlantic Multidecadal Oscillation). In the early 2000s, the area of the glacier dropped below 50% of its area at the end of the LIA. Geodetic mass balance measurements over 1983–2013 indicated −30.1 ± 1.7 m w.e. (−1 m w.e. yr−1) whereas glaciological mass balance measurements show −17.36 ± 2.9 m w.e. (−1.45 m w.e. yr−1) over 2001–2013, resulting in a doubling of the ablation rate in the last decade. In 2013 the maximum ice thickness was 59 ± 10.3 m. Assuming that the current ablation rate stays constant, Ossoue Glacier will disappear midway through the 21st century.
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Medynska-Gulij, Beata. "Who were cartographers of manuscript topographic maps in the Enlightenment?" Abstracts of the ICA 1 (July 15, 2019): 1–2. http://dx.doi.org/10.5194/ica-abs-1-247-2019.
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<p><strong>Abstract.</strong> The most difficult challenge is to provide the name of the cartographer, i.e. the author of graphic picture of topography with the use of watermedia on paper, for each important European topographic work. Even though we know the names of chiefs of survey and the most important engineers in field mapping teams, it is not possible to precisely describe their role in creating graphic style for fair copy. The aim of this study was to identify several types of design authorship of manuscript topographic maps in the Enlightenment.</p><p>Wrede’s map of Silesia was developed under King Frederick II’s supervision, who was himself theoretically and practically competent in map making. The mapping and the resulting protraction copy were made by Wrede and his team, but the draughtsmen were probably coordinated by Oelsnitz, head of the Potsdam drawing room. Such a hierarchical production structure, might also be recognized in the map of Norway developed by order of Huth &ndash; the Staatsminister and mathematician &ndash; who delegated the coordination of surveying and drawing activities to Staffeldt. In fact, the men responsible for the original map were cartographer Stabell and other engineers. A similar solution would explain the map of the Electorate of Hanover, produced by Hogrewe and his subordinate engineers, formally supervised by du Plat, but with the personal involvement of King George III in the decisions over segment division and cartographic content.</p><p>Institutional authorship, or maps produced by the head of a specific drawing room and his subordinate draughtsmen. The map of England, attributed to Gardner and the personnel of the Tower of London drawing room, was developed according to this system. Authorship in tandem: those engineers who performed field surveys and sketches, and later produced fair copies (e.g. Roy and Sandby’s map of Scotland) &ndash; the former drew topographic objects and the latter was the sole author of landform painting; Avico and Carello (map of Susa Valley) &ndash; both put their ink signatures on the map, independent of the cartouche content.</p><p>Collective authorship where the maps were produced by draughtsmen associated with particular drawing rooms or employed to draw maps according to the protracted copies supplied. The former included, for instance, the case of the map of NE France with Lorraine (from Naudin’s atelier) or the over 3,000 map segments (map of the Habsburg Dominion) developed by officers in Vienna. A further example would be the map of Austrian Netherlands, most probably involving draughtsmen educated in France.</p><p>The comparison of maps with the actual topographic situation in the countryside, also made us realize that the perception and cartographic work of various groups of map-making officers in similar cultural and surveying conditions, but in different topographic situations, might be interpreted as elements in a broader phenomenon of the understanding of space in the Enlightenment. The use of water-based media allowed for the representation of lands throughout Europe. No other technique offered map makers and artists an opportunity to reflect landscape so realistically. It is, no wonder, then, that it strongly affected the development of modern principles for cartographic design, even being translated through into the engraving and lithographic world of print. The map-making initiatives conducted in the Enlightenment were distinctive, helping define an age and a new emerging Europe. In these manuscript maps, we can see how eighteenth-century European contemporaries helped develop conventions &ndash; in the use of line, color, perspective, tone and topographic form &ndash; that shaped how their world was seen: on maps, in art, in the political imagination.</p>
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Tresca, Antoine, Marie-Hélène Ruz, Stéphane Raison, and Pascal Grégoire. "MANAGEMENT OF AEOLIAN SAND TRANSPORT ON A DIKE, DUNKIRK SEAPORT, FRANCE." Coastal Engineering Proceedings 1, no. 33 (October 25, 2012): 91. http://dx.doi.org/10.9753/icce.v33.sediment.91.
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The shoreline of Dunkirk Seaport partly consists of a macrotidal beach oriented WSW-ENE backed by a 6 km long coated dike called “digue du Braek”. Aeolian sand transport was estimated on asphalt by means of sand traps. Also, time-averaged wind speed profiles were measured using cup anemometers under various wind velocities and directions along a transversal profile on the dike and the upper beach. High rates of sand transport enabled the setup of different kinds of experimental windbreaks on asphalt, in order to test potential dune formation on this kind of substrate. Under oblique onshore winds, it was regularly observed that amounts of sand captured in the traps placed on the dike were more important than those in traps placed on the upper beach. These results were related to sand sources: windblown sand captured on the dike originated from the coastal dunes developed at the dike toe, while sand trapped on the upper beach came from the tidal zone were aeolian transport is limited by complex intertidal bar-trough topography. It also appeared from the topographic surveys carried out on the windbreaks that although their location seemed to play a major role on the amount of sand captured, fences and synthetic fabrics deployed on sandy surfaces were also able to trap windblown sand on the seaport dike.
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Wainwright, Haruko M., Anna K. Liljedahl, Baptiste Dafflon, Craig Ulrich, John E. Peterson, Alessio Gusmeroli, and Susan S. Hubbard. "Mapping snow depth within a tundra ecosystem using multiscale observations and Bayesian methods." Cryosphere 11, no. 2 (April 3, 2017): 857–75. http://dx.doi.org/10.5194/tc-11-857-2017.
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Abstract. This paper compares and integrates different strategies to characterize the variability of end-of-winter snow depth and its relationship to topography in ice-wedge polygon tundra of Arctic Alaska. Snow depth was measured using in situ snow depth probes and estimated using ground-penetrating radar (GPR) surveys and the photogrammetric detection and ranging (phodar) technique with an unmanned aerial system (UAS). We found that GPR data provided high-precision estimates of snow depth (RMSE = 2.9 cm), with a spatial sampling of 10 cm along transects. Phodar-based approaches provided snow depth estimates in a less laborious manner compared to GPR and probing, while yielding a high precision (RMSE = 6.0 cm) and a fine spatial sampling (4 cm × 4 cm). We then investigated the spatial variability of snow depth and its correlation to micro- and macrotopography using the snow-free lidar digital elevation map (DEM) and the wavelet approach. We found that the end-of-winter snow depth was highly variable over short (several meter) distances, and the variability was correlated with microtopography. Microtopographic lows (i.e., troughs and centers of low-centered polygons) were filled in with snow, which resulted in a smooth and even snow surface following macrotopography. We developed and implemented a Bayesian approach to integrate the snow-free lidar DEM and multiscale measurements (probe and GPR) as well as the topographic correlation for estimating snow depth over the landscape. Our approach led to high-precision estimates of snow depth (RMSE = 6.0 cm), at 0.5 m resolution and over the lidar domain (750 m × 700 m).
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Höffle, Hannes, Cindy J. G. Van Damme, Clive Fox, Stéphanie Lelièvre, Christophe Loots, Richard D. M. Nash, Sandrine Vaz, Peter J. Wright, and Peter Munk. "Linking spawning ground extent to environmental factors — patterns and dispersal during the egg phase of four North Sea fishes." Canadian Journal of Fisheries and Aquatic Sciences 75, no. 3 (March 2018): 357–74. http://dx.doi.org/10.1139/cjfas-2016-0310.
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Previous studies have shown that four commercially important demersal species, namely Atlantic cod (Gadus morhua), haddock (Melanogrammus aeglefinus), whiting (Merlangius merlangus), and European plaice (Pleuronectes platessa), spawn in distinct areas across the North Sea. Based on two comprehensive ichthyoplankton surveys in 2004 and 2009, the present study uses generalized additive mixed models to delimit these spawning grounds using the distribution of recently spawned eggs, investigates their relationship to specific environmental conditions, and examines egg dispersal during their development. Results indicate that presence–absence of early stage eggs is more related to temporal and topographic variables, while egg densities are closely linked with hydrography. Egg distribution patterns were relatively consistent during development and only changed near hatching. Compared with historic observations, the location of the spawning grounds appeared stable on the broad scale but centres of egg abundance varied between the surveyed years. Potential effects of long-term climate change and anthropogenic short-term disturbances, such as seismic surveys, on fish reproduction are discussed, pointing out the demand for multispecies studies on these issues.
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Gundlach, Erich, Eugene A. Pavia, Clay Robinson, and James C. Gibeaut. "Shoreline Surveys at the Exxon Valdez Oil Spill: The State of Alaska Response." International Oil Spill Conference Proceedings 1991, no. 1 (March 1, 1991): 519–29. http://dx.doi.org/10.7901/2169-3358-1991-1-519.
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ABSTRACT The state of Alaska needs information on the shoreline impacts of the Exxon Valdez incident to determine the linear extent of affected shoreline and the degree of oil penetration into the beach versus surface coverage, to assist the shoreline treatment effort, and to monitor oil persistence. Three principal methods were used to obtain data. Low-altitude helicopter surveys were made repeatedly during the first months of the incident to define shoreline impacts as heavy, moderate, light, and “no observed oiling.” A total of 140 ground stations in Prince William Sound, and over 60 stations in the Kenai and Kodiak areas, were set up to make specific measurements of surface coverage, oil penetration, and oil thickness along a topographic profile. An extensive (more than 1,400 km) walking survey was mounted after the 1989 treatment season to determine the extent of oil remaining and to guide the 1990 cleanup effort. More than 160 km of shoreline remained moderately to heavily oiled in the three regions at the end of 1989. Collected data were entered into the Alaska Department of Environmental Conservation geographic information system to enable map production, database queries, and report creation. On an as-needed basis, data derived from these surveys were presented to the state on-scene coordinator, other state and federal agencies, and the cleanup operation.
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Homan, Joel W., and Douglas L. Kane. "Arctic snow distribution patterns at the watershed scale." Hydrology Research 46, no. 4 (September 29, 2014): 507–20. http://dx.doi.org/10.2166/nh.2014.024.
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Watershed-scale hydrologic models require good estimates of spatially distributed snow water equivalent (SWE) at winter's end. Snow on the ground in arctic environments is susceptible to significant wind redistribution, which results in heterogeneous snowpacks. The scarcity and quality of data collected by snow gauges provides a poor indicator of actual snowpack distribution. Snow distribution patterns are similar from year to year because they are largely controlled by the interaction of topography, vegetation, and consistent weather patterns. Consequently, shallow and deep areas of snow tend to be spatially predetermined, resulting in depth (or SWE) differences that may vary as a whole, but not relative to each other. Our aim was to identify snowpack distribution patterns and establish their stability in time and space at a watershed scale. Snow patterns were established by: (1) using numerous field surveys from end-of-winter field campaigns; and (2) differentiating snowpacks that characterize small-scale anomalies (local scale) from snowpacks that represent a large-scale area (regional scale). We concluded that basic snow survey site descriptions could be used to separate survey locations into regional and local-scale representative sites. Removing local-scale influences provides a more accurate representation of the regional snowpack, which will aid in forecasting snowmelt runoff events.
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De M. Figueirôa, Silvia. "Charles Frederic Hartt and the ‘Geological Commission of Brazil’ (1875-1877)." Earth Sciences History 13, no. 2 (January 1, 1994): 168–73. http://dx.doi.org/10.17704/eshi.13.2.c5141486210264g4.
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The Geological Commission of Brazil (GCB) was created on April 30, 1875, within the Ministry of Agriculture in order to promote a systematic survey of Brazilian territory. Despite the fact that other scientific traditions were already present in Brazilian geology-e.g., the German and the French ones-the GCB model was inspired by the North American Geological Surveys. As the North American Surveys usually combined geology, topography, and agriculture, this model fit very well into Brazilian needs at that moment, for the country was experiencing intense economic development caused by the coffee agriculture boom, creating a strong demand for land with the appropriate soil for growing coffee. For the organization of the GCB the Brazilian government accepted a proposal made by the Canadian-born Charles Frederic Hartt (Fredericton, New Brunswick 1840-Rio de Janeiro, 1878), who was familiar both with Brazil and the North American Geological Surveys. Hartt had visited Brazil in 1865 as a member of the Thayer Expedition with Louis Agassiz. During the 32 month existence of the Commission, Hartt and the GCB staff covered a large part of the Brazilian Empire, collecting thousands of samples and preparing dozens of papers and reports most of which, unfortunately, remained unpublished. The demise of the GCB was ordered in 1878 by a new ministry for budgetary reasons. Nevertheless, it provided an institutional model which inspired the later Geographical and Geological Commission of Sao Paulo (1886) as well as the Geological and Mineralogical Survey of Brazil (1907), which, in various manifestations, has continued to the present day.
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Stateczny, Andrzej, Marta Włodarczyk-Sielicka, and Grzegorz Zaniewicz. "Using High-Density Bathymetric Data for the Production of Precise ENC." Annual of Navigation 19, no. 2 (December 1, 2012): 99–108. http://dx.doi.org/10.2478/v10367-012-0020-x.
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Abstract Due to an increasing trend of replacing traditional paper navigational charts with electronic ones, requirements for the creation of new ENC have been steadily growing. One example is the precise electronic navigational chart, which is based on accurate mapping of topographic and hydrographic elements. Information about depth of the waters contained on the charts are crucial for the safety of navigation. During the production of precise navigational charts, bathymetric information acquired by a multi-beam sonar system (or swath-bathymetry interferometric system) is used. A multi-beam sonar system emits several signal beams from a single transducer in different directions, which allows to cover a hundred percent of the survey area. The authors of the article carried out an analysis of bathymetric data in terms of differences in their preparation for the production of precise ENC.
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Young, N., and I. Goodwin. "Comparison of Surface Characteristics of the Antarctic Ice Sheet with Satellite Observations (Abstract)." Annals of Glaciology 9 (1987): 253. http://dx.doi.org/10.1017/s0260305500000975.
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Ground surveys of the ice sheet in Wilkes Land, Antarctica, have been made on oversnow traverses operating out of Casey. Data collected include surface elevation, accumulation rate, snow temperature, and physical characteristics of the snow cover. By the nature of the surveys, the data are mostly restricted to line profiles. In some regions, aerial surveys of surface topography have been made over a grid network. Satellite imagery and remote sensing are two means of extrapolating the results from measurements along lines to an areal presentation. They are also the only source of data over large areas of the continent. Landsat images in the visible and near infra-red wavelengths clearly depict many of the large- and small scale features of the surface. The intensity of the reflected radiation varies with the aspect and magnitude of the surface slope to reveal the surface topography. The multi-channel nature of the Landsat data is exploited to distinguish between different surface types through their different spectral signatures, e.g. bare ice, glaze, snow, etc. Additional information on surface type can be gained at a coarser scale from other satellite-borne sensors such as ESMR, SMMR, etc. Textural enhancement of the Landsat images reveals the surface micro-relief. Features in the enhanced images are compared to ground-truth data from the traverse surveys to produce a classification of surface types across the images and to determine the magnitude of the surface topography and micro-relief observed. The images can then be used to monitor changes over time.
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Young, N., and I. Goodwin. "Comparison of Surface Characteristics of the Antarctic Ice Sheet with Satellite Observations (Abstract)." Annals of Glaciology 9 (1987): 253. http://dx.doi.org/10.3189/s0260305500000975.
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Ground surveys of the ice sheet in Wilkes Land, Antarctica, have been made on oversnow traverses operating out of Casey. Data collected include surface elevation, accumulation rate, snow temperature, and physical characteristics of the snow cover. By the nature of the surveys, the data are mostly restricted to line profiles. In some regions, aerial surveys of surface topography have been made over a grid network.Satellite imagery and remote sensing are two means of extrapolating the results from measurements along lines to an areal presentation. They are also the only source of data over large areas of the continent. Landsat images in the visible and near infra-red wavelengths clearly depict many of the large- and small scale features of the surface. The intensity of the reflected radiation varies with the aspect and magnitude of the surface slope to reveal the surface topography. The multi-channel nature of the Landsat data is exploited to distinguish between different surface types through their different spectral signatures, e.g. bare ice, glaze, snow, etc. Additional information on surface type can be gained at a coarser scale from other satellite-borne sensors such as ESMR, SMMR, etc. Textural enhancement of the Landsat images reveals the surface micro-relief.Features in the enhanced images are compared to ground-truth data from the traverse surveys to produce a classification of surface types across the images and to determine the magnitude of the surface topography and micro-relief observed. The images can then be used to monitor changes over time.
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AHNELT, PETER KURT, CHRISTIAN SCHUBERT, ANNA KÜBBER-HEISS, ALEXANDRA SCHIVIZ, and ELISABETH ANGER. "Independent variation of retinal S and M cone photoreceptor topographies: A survey of four families of mammals." Visual Neuroscience 23, no. 3-4 (May 2006): 429–35. http://dx.doi.org/10.1017/s095252380623342x.
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In mammals, cone photoreceptor subtypes are thought to establish topographies that reflect the species-relevant properties of the visual environment. Middle- to long-wavelength-sensitive (M) cones are the dominant population and in most species they form an area centralis at the visual axis. Short-wavelength-sensitive (S) cone topographies do not always match this pattern. We here correlate the interrelationship of S and M cone topographies in representatives of several mammalian orders with different visual ecology, including man, cheetah, cat, Eurasian lynx, African lion, wild hog, roe deer, and red deer. Retinas were labeled with opsin antisera and S and M cone distributions as well as S/M cone ratios were mapped. We find that species inhabiting open environments show M cone horizontal streaks (cheetah, pig, deer). Species living in structured habitats (tiger, lynx, red deer) have increased S cone densities along the retinal margin. In species with active vision (cheetah, bear, tiger, man), S cone distributions are more likely to follow the centripetal M cone gradients. Small species show a ventral bias of peak S cone density which either matches the peak of M cone density in a temporal area centralis (diurnal sciurid rodents, tree shrews) or not (cat, manul, roe deer).Thus, in addition to habitat structure, physical size and specific lifestyle patterns (e.g. food acquisition) appear to underlie the independent variations of M and S cone topographies.
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Guo, Shulan, Changhong Yan, Liangchen Yu, Yang Liu, Yinkang Zhou, and Xiaozhong Shi. "Characteristics, Controlling Factors, and Formation of Shallow Buried Karst in Eastern China: A Case Study in the Wuxi Metro Areas, Jiangsu Province." Environmental and Engineering Geoscience 26, no. 2 (May 27, 2020): 257–69. http://dx.doi.org/10.2113/eeg-2281.
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ABSTRACT Karst-related geo-disasters often occur in karst regions during underground construction. In recent years, a number of shallow buried karst features have been discovered in eastern China. Survey boreholes show that karst caves exist at depths of 26–30 m and 33–36 m, which are typical of shallow buried karst. Using cross-hole seismic computed tomographic techniques, 36 geological anomalies consisting of 26 mud-filled caves, three empty caves, and seven fissure zones/loose lens bodies were detected. Most of the karst caves were oblate or oval. After determining the scale of and the connection between the caves, the study area was divided into two areas to provide advice on the treatment of caves during construction. An analysis of the development characteristics of the karst suggests that karst is controlled by several key factors, including topography, structural features, groundwater conditions, and human activities. Following an analysis of these factors and field studies of the process of formation of the shallow buried caves, solutions are proposed to prevent karst-related geo-hazards. The research results can be used in the design of foundations for buildings that are located in regions that include shallow buried karst in eastern China.
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Rumpler, M., S. Daftry, A. Tscharf, R. Prettenthaler, C. Hoppe, G. Mayer, and H. Bischof. "Automated End-to-End Workflow for Precise and Geo-accurate Reconstructions using Fiducial Markers." ISPRS Annals of Photogrammetry, Remote Sensing and Spatial Information Sciences II-3 (August 7, 2014): 135–42. http://dx.doi.org/10.5194/isprsannals-ii-3-135-2014.
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Photogrammetric computer vision systems have been well established in many scientific and commercial fields during the last decades. Recent developments in image-based 3D reconstruction systems in conjunction with the availability of affordable high quality digital consumer grade cameras have resulted in an easy way of creating visually appealing 3D models. However, many of these methods require manual steps in the processing chain and for many photogrammetric applications such as mapping, recurrent topographic surveys or architectural and archaeological 3D documentations, high accuracy in a geo-coordinate system is required which often cannot be guaranteed. Hence, in this paper we present and advocate a fully automated end-to-end workflow for precise and geoaccurate 3D reconstructions using fiducial markers. We integrate an automatic camera calibration and georeferencing method into our image-based reconstruction pipeline based on binary-coded fiducial markers as artificial, individually identifiable landmarks in the scene. Additionally, we facilitate the use of these markers in conjunction with known ground control points (GCP) in the bundle adjustment, and use an online feedback method that allows assessment of the final reconstruction quality in terms of image overlap, ground sampling distance (GSD) and completeness, and thus provides flexibility to adopt the image acquisition strategy already during image recording. An extensive set of experiments is presented which demonstrate the accuracy benefits to obtain a highly accurate and geographically aligned reconstruction with an absolute point position uncertainty of about 1.5 times the ground sampling distance.
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Feurer, Denis, Olivier Planchon, Mohamed Amine El Maaoui, Abir Ben Slimane, Mohamed Rached Boussema, Marc Pierrot-Deseilligny, and Damien Raclot. "Using kites for 3-D mapping of gullies at decimetre-resolution over several square kilometres: a case study on the Kamech catchment, Tunisia." Natural Hazards and Earth System Sciences 18, no. 6 (June 7, 2018): 1567–82. http://dx.doi.org/10.5194/nhess-18-1567-2018.
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Abstract. Monitoring agricultural areas threatened by soil erosion often requires decimetre topographic information over areas of several square kilometres. Airborne lidar and remotely piloted aircraft system (RPAS) imagery have the ability to provide repeated decimetre-resolution and -accuracy digital elevation models (DEMs) covering these extents, which is unrealistic with ground surveys. However, various factors hamper the dissemination of these technologies in a wide range of situations, including local regulations for RPAS and the cost for airborne laser systems and medium-format RPAS imagery. The goal of this study is to investigate the ability of low-tech kite aerial photography to obtain DEMs with decimetre resolution and accuracy that permit 3-D descriptions of active gullying in cultivated areas of several square kilometres. To this end, we developed and assessed a two-step workflow. First, we used both heuristic experimental approaches in field and numerical simulations to determine the conditions that make a photogrammetric flight possible and effective over several square kilometres with a kite and a consumer-grade camera. Second, we mapped and characterised the entire gully system of a test catchment in 3-D. We showed numerically and experimentally that using a thin and light line for the kite is key for a complete 3-D coverage over several square kilometres. We thus obtained a decimetre-resolution DEM covering 3.18 km2 with a mean error and standard deviation of the error of +7 and 22 cm respectively, hence achieving decimetre accuracy. With this data set, we showed that high-resolution topographic data permit both the detection and characterisation of an entire gully system with a high level of detail and an overall accuracy of 74 % compared to an independent field survey. Kite aerial photography with simple but appropriate equipment is hence an alternative tool that has been proven to be valuable for surveying gullies with sub-metric details in a square-kilometre-scale catchment. This case study suggests that access to high-resolution topographic data on these scales can be given to the community, which may help facilitate a better understanding of gullying processes within a broader spectrum of conditions.
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Chand, Pritam, Milap Chand Sharma, Rakesh Bhambri, Chandrashekhar V. Sangewar, and Navin Juyal. "Reconstructing the pattern of the Bara Shigri Glacier fluctuation since the end of the Little Ice Age, Chandra valley, north-western Himalaya." Progress in Physical Geography: Earth and Environment 41, no. 5 (September 25, 2017): 643–75. http://dx.doi.org/10.1177/0309133317728017.
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The pattern of glacial records since the end of the Little Ice Age (LIA) are essential for evaluating glacier fluctuations and their link to post-LIA climate change. Although recession of the Himalayan glaciers is well-documented in this period, debate continues as to the magnitude and accuracy of estimated recession rates. This study presents a reconstruction of the pattern of fluctuations at the Bara Shigri Glacier in the Himachal Himalaya during the termination of the LIA (∼1850). A multi-data integrative analysis (MDIA) technique consisting of repeat terrestrial photographs, historical archives and reports, geomorphological evidence and maps, and high to medium spatial resolution satellite images (Corona, Hexagon, Landsat and WorldView-2) was used with supplemented by extensive field validation. The results indicate that during the early part of the 19th century the terminus of Bara Shigri Glacier was at ∼3900 m asl. Following this, there was a continuous recession with a total retreat of 2898 ± 50 m, which corresponds to a frontal areal loss of 4 ± 1 km2 in the last 151 years (1863–2014). Compared to this, during the last half century (1965–2014), the glacierised area was reduced by 1.1 ± 0.02 km2 with a concomitant terminus retreat of 1100 ± 32 m. The early 19th century advance is ascribed to a combination of cooling during this period, glacier topographical characteristics and contributions from steep-fronted avalanching tributaries. The late 19th century recession can be attributed to an overall increase in the temperature with a corresponding decrease in precipitation in the north-western Himalaya. Results are at variance with earlier, larger estimates of the frontal area loss for the Bara Shigri Glacier using either Survey of India (SoI) topographic maps or coarse spatial resolution satellite images (e.g. Landsat MSS) as historical datasets, and demonstrate the utility of mixed method approaches including higher-resolution satellite imagery for accurate estimation of glacier behaviour in this region.
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Kim, Heesoo, Chang-Rae Lee, Sang-kyu Lee, Seung-Yoon Oh, and Won Kim. "Biodiversity and Community Structure of Mesozooplankton in the Marine and Coastal National Park Areas of Korea." Diversity 12, no. 6 (June 10, 2020): 233. http://dx.doi.org/10.3390/d12060233.
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Zooplankton communities are useful bioindicators that can provide information on the changes occurring in marine ecosystems. Therefore, investigation of zooplankton communities in marine and coastal national parks is essential. However, the surveys of zooplankton communities using morphological identification require considerable time and labor. Metabarcoding is a practical alternative that can detect various taxa simultaneously. In this study, metabarcoding was newly applied along with the traditional morphological identification to establish a method for zooplankton community survey in the Marine and Coastal National Park areas of Korea. By comparing the results of these two identification methods, the strengths and limitations of metabarcoding were verified with the zooplankton communities appearing in these areas. The sensitive detection capability of metabarcoding enabled the identification of potential bioindicator taxa associated with external factors (e.g., water temperature, salinity, topography, and chlorophyll a concentration) in these national parks. We propose the use of metabarcoding for efficient surveys of mesozooplankton communities in the Marine and Coastal National Parks to establish monitoring of bioindicator taxa. It is also necessary to continuously search for taxa with high research value in these national parks using metabarcoding. Establishing an ongoing monitoring system that employs this approach can provide an effective tool for managing marine ecosystems in the Marine and Coastal National Parks.
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Salameh, Edward, Frédéric Frappart, Rafael Almar, Paulo Baptista, Georg Heygster, Bertrand Lubac, Daniel Raucoules, et al. "Monitoring Beach Topography and Nearshore Bathymetry Using Spaceborne Remote Sensing: A Review." Remote Sensing 11, no. 19 (September 21, 2019): 2212. http://dx.doi.org/10.3390/rs11192212.
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With high anthropogenic pressure and the effects of climate change (e.g., sea level rise) on coastal regions, there is a greater need for accurate and up-to-date information about the topography of these systems. Reliable topography and bathymetry information are fundamental parameters for modelling the morpho-hydrodynamics of coastal areas, for flood forecasting, and for coastal management. Traditional methods such as ground, ship-borne, and airborne surveys suffer from limited spatial coverage and temporal sampling due to logistical constraints and high costs which limit their ability to provide the needed information. The recent advancements of spaceborne remote sensing techniques, along with their ability to acquire data over large spatial areas and to provide high frequency temporal monitoring, has made them very attractive for topography and bathymetry mapping. In this review, we present an overview of the current state of spaceborne-based remote sensing techniques used to estimate the topography and bathymetry of beaches, intertidal, and nearshore areas. We also provide some insights about the potential of these techniques when using data provided by new and future satellite missions.
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Lane, Belize A., Gregory B. Pasternack, Helen E. Dahlke, and Samuel Sandoval-Solis. "The role of topographic variability in river channel classification." Progress in Physical Geography: Earth and Environment 41, no. 5 (July 24, 2017): 570–600. http://dx.doi.org/10.1177/0309133317718133.
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To date, subreach-scale variations in flow width and bed elevation have rarely been included in channel classifications. Variability in topographic features of rivers, however, in conjunction with sediment supply and discharge produces a mosaic of channel forms that provides unique habitats for sensitive aquatic species. In this study we investigated the utility of topographic variability attributes (TVAs) in distinguishing channel types and dominant channel formation and maintenance processes in montane and lowland streams of the Sacramento River basin, California, USA. A stratified random survey of 161 stream sites was performed to ensure balanced sampling across groups of stream reaches with expected similar geomorphic settings. For each site surveyed, width and depth variability were measured at baseflow and bankfull stages, and then incorporated in a channel classification framework alongside traditional reach-averaged geomorphic attributes (e.g., channel slope, width-to-depth, confinement, and dominant substrate) to evaluate the significance of TVAs in differentiating channel types. In contrast to more traditional attributes such as slope and contributing area, which are often touted as the key indicators of hydrogeomorphic processes, bankfull width variance emerged as a first-order attribute for distinguishing channel types. A total of nine channel types were distinguished for the Sacramento Basin consisting of both previously identified and new channel types. The results indicate that incorporating TVAs in channel classification provides a quantitative basis for interpreting nonuniform as well as uniform geomorphic processes, which can improve our ability to distinguish linked channel forms and processes of geomorphic and ecological significance.
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Chiarini, S., S. Cremonesi, L. Fregonese, F. Fassi, and L. Taffurelli. "A multi-range approach for Cultural Heritage survey: a case study in Mantua Unesco site." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XL-5 (June 6, 2014): 157–64. http://dx.doi.org/10.5194/isprsarchives-xl-5-157-2014.
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In this paper, a Cultural Heritage survey, performed by employing and integrating different type of acquisition technologies (imagebased and active sensor based) is presented. The aim of the survey is to create a 3D multiscale database, therefore, different restitution scales, from the architectural-urban one to a detail one are taken in consideration. This research is part of a project financed by the Unesco for the study of historical gardens located in Mantua and Sabbioneta, and in particular for the <i>Palazzo Te</i> renaissance gardens in Mantua, which are reported in this paper. First of all, a general survey of the area has been realized by employing the classical aerial photogrammetry in order to provide the actual arboreal and urban furniture conditions of the gardens (1:500 scale). Next, a detailed photogrammetric survey of the Esedra courtyard in <i>Palazzo Te</i> has been performed by using a UAV system. At the end, laser scanning and traditional topography have been used for the terrestrial detailed acquisition of gardens and architectural façades (1:50–1:20 scale). The aim of this research is to create a suitable graphical documentation support for the study of the structure of the gardens, to analyze how they have been modified over the years and as an effective support for eventual future re-design. Moreover, the research has involved a certain number of botanic and archeological investigations, which have been duly acquired and modeled with image based systems.<br><br> Starting from the acquired datasets with their acquisition scales, a series of comparative analysis have been performed, especially for those areas in which all the systems have been employed. The comparisons have been extracted by analyzing point cloud models obtained by using a topographical network.<br><br> As a result, the multi-range approach efficiency, obtained by employing the actual available technologies have been illustrated in the present work.
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Xanthakis, Michail, Kosmas Pavlopoulos, Vasilios Kapsimalis, Georgios Apostolopoulos, Gavriil Xanthopoulos, Panagiotis Stefanidis, and Niki Evelpidou. "Prediction of Soil Loss in a Reservoir Watershed Using an Erosion Model and Modern Technological Tools: A Case Study of Marathon Lake, Attica in Greece." Environmental Sciences Proceedings 2, no. 1 (September 7, 2020): 63. http://dx.doi.org/10.3390/environsciproc2020002063.
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Marathon Lake is an artificial reservoir with great environmental, ecological, social, and economic significance because it was the main source of water for Athens, the capital of Greece, for many years. The present study details the first attempt to map sedimentation in Marathon Lake in detail, using bathymetric mapping and soil erosion field surveying of the torrent watershed areas. First, the results of a bathymetric survey carried out in 2011 were compared with topographic maps that pre-date the construction of the dam. Based on this comparison, an estimated 8.34 hm3 of sediment have been deposited in the 80 years since the dam’s construction. In the current survey, the Revised Universal Soil Loss Equation (RUSLE) was used to estimate soil loss in the watershed area of the streams that end in Marathon Lake. The estimated value from the RUSLE was substantially lower (3.02 hm3) than that calculated in the bathymetric survey.
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Zingerle, P., R. Pail, M. Scheinert, and T. Schaller. "Evaluation of terrestrial and airborne gravity data over Antarctica – a generic approach." Journal of Geodetic Science 9, no. 1 (January 1, 2019): 29–40. http://dx.doi.org/10.1515/jogs-2019-0004.
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Abstract The AntGrav project, funded by the German Research Foundation (DFG) has the main objective to homogenize and optimize Antarctic gravity field information. Within this project an evaluation procedure is needed to inspect all different kind of gravity field surveys available in Antarctica. In this paper a suitable methodology is proposed. We present an approach for fast 3D gravity point data reduction in different spectral bands. This is achieved through pre-calculating a fine 3D mesh of synthesized gravity functionals over the entirety of the Antarctic continent, for which two different global models are used: the combined satellite model GOCO05s for the long-wavelength part, and the topographic model Earth2014 for the shorter wavelengths. To maximize the applicability separate meshes are calculated for different spectral bands in order to specifically reduce a certain band or a selected combination. All meshes are calculated for gravity anomalies as well as gravity disturbances. Utilizing these meshes, synthesized gravity data at arbitrary positions is computed by conventional 3D interpolation methods (e.g. linear, cubic or spline). It is shown that the applied approach can reach a worst-case interpolation error of less than 1 mGal. Evaluation results are presented for the AntGG grid and exemplary for the in-situ measurements of the AGAP and BAS-LAND campaigns. While general properties, large-scale errors and systematic effects can usually be detected, small-scale errors (e.g. of single points) are mostly untraceable due to the uncertainties within the topographic model.
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Marti, R., S. Gascoin, T. Houet, O. Ribière, D. Laffly, T. Condom, S. Monnier, et al. "Evolution of Ossoue Glacier (French Pyrenees) since the end of the Little Ice Age." Cryosphere 9, no. 5 (September 8, 2015): 1773–95. http://dx.doi.org/10.5194/tc-9-1773-2015.
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Abstract. Little is known about the fluctuations of the Pyrenean glaciers. In this study, we reconstructed the evolution of Ossoue Glacier (42°46' N, 0.45 km2), which is located in the central Pyrenees, from the Little Ice Age (LIA) onwards. To do so, length, area, thickness, and mass changes in the glacier were generated from historical data sets, topographical surveys, glaciological measurements (2001–2013), a ground penetrating radar (GPR) survey (2006), and stereoscopic satellite images (2013). The glacier has receded considerably since the end of the LIA, losing 40 % of its length and 60 % of its area. Three periods of marked ice depletion were identified: 1850–1890, 1928–1950, and 1983–2013, as well as two short periods of stabilization: 1890–1894, 1905–1913, and a longer period of slight growth: 1950–1983; these agree with other Pyrenean glacier reconstructions (Maladeta, Coronas, Taillon glaciers). Pyrenean and Alpine glaciers exhibit similar multidecadal variations during the 20th century, with a stable period detected at the end of the 1970s and periods of ice depletion during the 1940s and since the 1980s. Ossoue Glacier fluctuations generally concur with climatic data (air temperature, precipitation, North Atlantic Oscillation, Atlantic Multidecadal Oscillation). Geodetic mass balance over 1983–2013 was −1.04 ± 0.06 w.e.a−1 (−31.3 ± 1.9 m w.e.), whereas glaciological mass balance was −1.45 ± 0.85 m w.e. a−1 (−17.3 ± 2.9 m w.e.) over 2001–2013, resulting in a doubling of the ablation rate in the last decade. In 2013 the maximum ice thickness was 59 ± 10.3 m. Assuming that the current ablation rate remains constant, Ossoue Glacier will disappear midway through the 21st century.
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Kar, Gouranga, Ravender Singh, and Harsh Nath Verma. "Spatial variability studies of soil hydro-physical properties using GIS for sustainable crop planning of a watershed of eastern India and its testing in a rainfed rice area." Soil Research 42, no. 4 (2004): 369. http://dx.doi.org/10.1071/sr03133.
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In this study soil hydro-physical properties such as soil texture, available water capacity, and organic carbon, along with existing land use and topography of a representative watershed of eastern India (Kadalipal watershed, 20.80–20.86°N and 85.54–86.50°E, Dhenkanal district, Orissa), were spatially mapped after collecting data from different sources (ground-truthing, profile survey, remote sensing satellite imagery). Since availability of water is confined to the south-west monsoon period (rainy season, June–September), eastern India is mainly mono-cropped, dominated by rice but second crops can be planned based on the soil hydro-physical properties, mainly water retention and available water of the soil profile utilising residual soil moisture. Keeping the existing land use as a base and considering the potential and prospects of soil hydro-physical properties in different topographies, in this investigation, an alternative land-use plan was developed in different parts of the watershed and tested in its rainfed rice area. Since direct measurement of available water capacity or soil water constants over a large area is time-consuming, pedo-transfer functions were also developed to predict soil water constants using easily measured parameters (e.g. cation exchange capacity, organic carbon, oven-dry bulk density, soil texture, calcium carbonate, etc.) of arable land of the watershed. Results of implementation revealed that the new cropping system was practical for increasing production, productivity, profitability, and sustainability of the rainfed rice area of the eastern India.
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Hussain, M., and D. Chen. "Creating a three level building classification using topographic and address-based data for Manchester." ISPRS Annals of Photogrammetry, Remote Sensing and Spatial Information Sciences II-2 (November 11, 2014): 67–73. http://dx.doi.org/10.5194/isprsannals-ii-2-67-2014.
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Buildings, the basic unit of an urban landscape, host most of its socio-economic activities and play an important role in the creation of urban land-use patterns. The spatial arrangement of different building types creates varied urban land-use clusters which can provide an insight to understand the relationships between social, economic, and living spaces. The classification of such urban clusters can help in policy-making and resource management. In many countries including the UK no national-level cadastral database containing information on individual building types exists in public domain. In this paper, we present a framework for inferring functional types of buildings based on the analysis of their form (e.g. geometrical properties, such as area and perimeter, layout) and spatial relationship from large topographic and address-based GIS database. Machine learning algorithms along with exploratory spatial analysis techniques are used to create the classification rules. The classification is extended to two further levels based on the functions (use) of buildings derived from address-based data. The developed methodology was applied to the Manchester metropolitan area using the Ordnance Survey‟s MasterMap®, a large-scale topographic and address-based data available for the UK.
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Wilbrand, H., and W. Rauschning. "Investigation of Temporal Bone Anatomy by Plastic Moulding and Cryomicrotomy." Acta Radiologica. Diagnosis 27, no. 4 (July 1986): 389–94. http://dx.doi.org/10.1177/028418518602700404.
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To increase our understanding of the complex topographic relations between temporal bone structures and to facilitate the interpretation of their radiographic images, two techniques were developed. 1) Plastic moulding of temporal bone specimens using polyester resin and silicone rubber substances providing detailed information and a three-dimensional survey of the structures. Carefully macerated temporal bone specimens are filled with plastic material under vacuum and the bone is then dissolved. The preparations, freed from irrelevant structures and embellished, allow metric evaluation of the different structures and their topographic relations. 2) Automatic serial cryomicrotomy of fresh, deep-frozen temporal bones, using a commercial sledge-cryomicrotome. Photography of the cut surfaces of the specimen, usually at distances of 0.25 to 0.50 mm, allows natural-colour reproduction of minute detail, e.g. the melanin cell area in the cochlea, the smallest vessels on the ossicular surfaces, and the origin of the cochlear aqueduct at the basal turn of the cochlea. By correlating the photographs with images from the corresponding tomographic planes accurate information is obtained for interpretation of the radiographic images. A combination of the two techniques facilitates a detailed study and is a valuable aid in the teaching of temporal bone anatomy.
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Rengers, Francis K., Thomas D. Rapstine, Michael Olsen, Kate E. Allstadt, Richard M. Iverson, Ben Leshchinsky, Maciej Obryk, and Joel B. Smith. "Using High Sample Rate Lidar to Measure Debris-Flow Velocity and Surface Geometry." Environmental and Engineering Geoscience 27, no. 1 (January 8, 2021): 113–26. http://dx.doi.org/10.2113/eeg-d-20-00045.
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ABSTRACT Debris flows evolve in both time and space in complex ways, commonly starting as coherent failures but then quickly developing structures such as roll waves and surges. These processes are readily observed but difficult to study or quantify because of the speed at which they evolve. Many methods for studying debris flows consist of point measurements (e.g., flow height or basal stresses), which are inherently limited in spatial coverage and cannot fully characterize the spatiotemporal evolution of a flow. In this study, we use terrestrial lidar to measure debris-flow profiles at high sampling rates to examine debris-flow movement with high temporal and spatial precision and accuracy. We acquired measurements during gate-release experiments at the U.S. Geological Survey debris-flow flume, a unique experimental facility where debris flows can be artificially generated at a large scale. A lidar scanner was used to record repeat topographic profiles of the moving debris flows along the length of the flume with a narrow swath width (∼1 mm) at a rate of 60 Hz. The high-resolution lidar profiles enabled us to quantify flow front velocity of the debris flows and provided an unprecedented record of the development and evolution of the flow structure with a sub-second time resolution. The findings of this study demonstrate how to obtain quantitative measurements of debris-flow movement. In addition, the data help us to quantitatively define the development of a saltating debris-flow front and roll waves behind the debris-flow front. Such measurements may help constrain future modeling efforts.