Flowing stream networks extend and retract as their surrounding landscapes wet up and dry out, both seasonally and during rainstorms, with implications for aquatic ecosystems and greenhouse gas ...exchange. Some networks are much more dynamic than others, however, and the reasons for this difference are unknown. Here we show that the tendency of stream networks to extend and retract can be predicted from down‐valley changes in topographic attributes (slope, curvature, and contributing drainage area), without measuring subsurface hydrologic properties. Topography determines where water accumulates within valley networks, and we propose that it also modulates flow partitioning between the surface and subsurface. Measurements from 17 mountain stream networks support this hypothesis, showing that undissected valley heads have greater subsurface transport capacities than sharply incised valleys downstream. In catchments where broad valley heads rapidly transition to sharply incised valleys, subsurface transport capacity decreases abruptly, stabilizing stream length through wet and dry periods.
Plain Language Summary
Although stream networks are represented as fixed blue lines on maps, the actual extent of flowing water dynamically adjusts as landscapes become wetter and drier. This is an old observation, but one without a satisfying physical explanation. Intuitively, flowing streams extend during wetter periods, as smaller parts of the landscape are able to supply enough water to support streamflow. But the supply of water is only part of the story, because some parts of the landscape may have greater capacity to move supplied water through the subsurface without streamflow, affecting where water ultimately emerges. In this study, we use observations from 17 mountainous landscapes to show that topography can be used to predict both the supply of water and the capacity to move that water through the subsurface. Consequently, topographic maps can tell us how much a stream network will extend as its surrounding landscape becomes wetter. This helps us predict how dynamic (or, conversely, stable) stream networks will be during rainstorms, droughts, and longer‐term climatic shifts.
Key Points
Some flowing stream networks lengthen dramatically as their catchments become wetter, whereas others change much less
This tendency for networks to extend and retract can be predicted from down‐valley changes in slope, drainage area, and curvature
As valleys become more sharply incised downstream, subsurface transmissivity decreases, which helps stabilize flowing stream length
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A sense of space in postrhinal cortex LaChance, Patrick A; Todd, Travis P; Taube, Jeffrey S
Science (American Association for the Advancement of Science),
07/2019, Volume:
365, Issue:
6449
Journal Article
Peer reviewed
Open access
A topographic representation of local space is critical for navigation and spatial memory. In humans, topographic spatial learning relies upon the parahippocampal cortex, damage to which renders ...patients unable to navigate their surroundings or develop new spatial representations. Stable spatial signals have not yet been observed in its rat homolog, the postrhinal cortex. We recorded from single neurons in the rat postrhinal cortex whose firing reflects an animal's egocentric relationship to the geometric center of the local environment, as well as the animal's head direction in an allocentric reference frame. Combining these firing correlates revealed a population code for a stable topographic map of local space. This may form the basis for higher-order spatial maps such as those seen in the hippocampus and entorhinal cortex.
The temporal and spatial information of electroencephalogram (EEG) are essential for the emotion recognition model to learn the discriminative features. Hence, we propose a novel hybrid ...spatial-temporal feature fusion neural network (STFFNN) to extract the discriminative features and integrate complementary information. The generated power topographic maps, which capture dependencies among the electrodes, are fed to convolutional neural network (CNN) for spatial feature learning. Furthermore, instance normalizations (INs) and batch normalizations (BNs) within the CNN are appropriately combined to alleviate the individual difference and preserve the domain-invariant information. Meanwhile, a feedforward network is adopted for temporal feature learning. Due to the high dimensionality of EEG features, we propose a grid-search-based configurational optimization method to robustly reduce the dimensionality. Finally, inspired by the multimodal fusion strategies that leverage the complementarity of data to obtain more robust predictions, we utilize a bidirectional long short-term memory (Bi-LSTM) network for temporal and spatial feature fusion. To validate the effectiveness of the proposed method, the tenfold cross-validation experiments and subject-dependent experiments are both conducted on the DEAP database. The experimental results demonstrate that the proposed method achieves outstanding performance in emotion recognition with arousal and valence level.
The purpose of the current study is an attempt to characterize the scientific and practical issues of modern topographic data preparation and its use in geological exploration. The study is based on ...the long-term author’s experience in cartographic support of field and cameral geological and geophysical works and on the analysis of modern research in topographical mapping. The specifics of providing access to modern topographic data in the Russian Federation, the Republic of India and the Republic of Colombia, where the main experimental work has been carried out, are briefly described. The content features of the topographic map sheets of these countries are shortly summarized. Practical results of solving such exploration tasks as survey network design, creation of terrain sketch, processing and interpretation of geological and geophysical data, creation of digital terrain models, and preparation of base maps for web services are presented. The prospective directions for further research in improving the use of topographic data in geological exploration are given. It has been found that topographic maps and data are increasingly being used as base layers in the creation of the modern web map services. A balanced and critical approach to the use of global topographic data resources is need for geological exploration as a state’s strategic activity. The industry needs publicly available national multiscale topographic maps as well as theoretical and methodological foundations for the use of web mapping advances in mineral prospecting and exploration.
Context
Cultural landscapes evolve over time. However, the rate and direction of change might not be in line with societal needs and more information on the forces driving these changes are therefore ...needed.
Objectives
Filling the gap between single case studies and meta-analyses, we present a comparative study of landscape changes and their driving forces based in six regions across Europe conducted using a consistent method.
Methods
A LULC analysis based on historical and contemporary maps from the nineteenth and twentieth century was combined with oral history interviews to learn more about perceived landscape changes, and remembered driving forces. Land cover and landscape changes were analysed regarding change, conversions and processes. For all case study areas, narratives on mapped land cover change, perceived landscape changes and driving forces were compiled.
Results
Despite a very high diversity in extent, direction and rates of change, a few dominant processes and widespread factors driving the changes could be identified in the six case study areas, i.e. access and infrastructure, political shifts, labor market, technological innovations, and for the more recent period climate change.
Conclusions
Grasping peoples’ perception supplements the analyses of mapped land use and land cover changes and allows to address perceived landscape changes. The list of driving forces determined to be most relevant shows clear limits in predictability: Whereas changes triggered by infrastructural developments might be comparatively easy to model, political developments cannot be foreseen but might, nevertheless, leave major marks in the landscape.
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During the Cold War, the Soviet military carried out an ambitious mapping programme, which resulted in a global series of topographic maps. Although recent advances in scholarship have increased our ...knowledge of the production of these maps, we still know little about the organization behind them. Based on information from a set of 466 1:50 000-scale Soviet military topographic maps of Denmark, this article examines the Soviet mapping practices related to the large-scale mapping of Denmark. Results show that the Soviet military compiled large-scale topographic maps of Denmark between the 1950s and the 1980s. The maps were initially based on Danish maps, but later the Soviets began to prefer remote-sensed data from satellite imagery. This allowed the Soviets to capture information about concealed military infrastructure. The article also shows the potential for using information from the map sheets in a transnational analysis of the Soviet mapping during the Cold War.
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Determining the topographic map scale is a critical basis for assessing the degree of confidentiality of topographic maps. In this study, we propose a solution to the challenge of estimating the ...scale of fragmented raster topographic maps by leveraging a priori knowledge of scale-related features, constructing an expert knowledge image pyramid dataset (EKIPD) under guided expert knowledge, and applying deep convolutional neural network algorithms to create a hybrid intelligent model that synergistically combines knowledge, data, and algorithm. The EKIPD dataset captures a representative sample distribution of fragmented topographic maps of varying sizes, which enables us to statistically determine the optimal recognition size (ORS) for sub-map recognition. The ORS then serves as a stepping threshold to partition the topographic maps into recognizable sub-maps. Each sub-map is independently processed through the model to obtain individual predictions, which are subsequently integrated to infer the map scale. E
Lee, C.K.; Yun, K.; He, G., and Park, B.W., 2021. Estimation of submerged coast by existing survey data and topographic survey. In: Lee, J.L.; Suh, K.-S.; Lee, B.; Shin, S., and Lee, J. (eds.), ...Crisis and Integrated Management for Coastal and Marine Safety. Journal of Coastal Research, Special Issue No. 114, pp. 449–453. Coconut Creek (Florida), ISSN 0749-0208. The purpose of this study is to investigate whether registered land located on a coast is submerged during high tide. The most important data when judging whether the registered coastal land is submerged are cadastral maps and topographic maps. In Korea, all land parcels have been registered in the land ledger and cadastral map in the 1910s. A land ledger is a document that contains the address, area, title, grade, and owner of the parcel, whereas a cadastral map is a graphical representation that contains the location and boundary of a parcel. Even if the boundary of the parcel changes at the site, the boundary of the cadastral map remains unchanged before the land register is modified officially by the request of the owner. For submerged land, two cases exist. Case 1 is after the land is submerged and left without restoration. Case 2 is after the land has been restored following its submersion. In case 1, the coastline of a submerged land can be surveyed by surveying in situ. However, in case 2, the coastline cannot be surveyed at the time it is submerged. In this study, a coastline is extracted using aerial images after it was submerged. When the coordinate systems of the cadastral and topographic maps are the same, changes in the land boundary can be determined easily by overlaying the two maps based on the absolute coordinate system. However, if the coordinate systems of the two maps are different, then another method is required. A simple method is to translate and rotate a map based on the boundary lines of features displayed on two maps to overlay another map at the appropriate location. In this study, a cadastral map is translated and rotated on a topographic map based on boundary lines of unchanged features on two maps to determine whether a coastal land is submerged. The proposed method renders it easy to determine whether land is submerged as well as the amount of parcel area submerged.
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