Spatial Mapping System Research Articles

A STUDY OF RAPID MAPPING TECHNOLOGY BASED ON ADOBE ILLUSTRATOR

Abstract. At present, China's urban and rural construction, national security, emergency and disaster relief have put forward higher and faster requirements for high-quality and current maps. How to use the latest spatial database in the shortest possible time to produce and provide high-quality, highly presentable, content-rich maps is an urgent issue. In this paper, we study the rapid mapping technology based on GIS platform and map mapping software, study the automatic map mapping method under AI environment, design and develop the spatial basic geographic database-driven rapid mapping system, realize the automatic lossless conversion of GIS data to map mapping software according to the established mapping rule base, realize the automatic configuration of symbols and annotations, and realize the automation of processing of element relationship. The AI-based database-driven rapid mapping technology has been used in the practice of map compilation in prefecture-level cities, replacing most of the manual repetitive operations, greatly improving the efficiency of map compilation, and enhancing the capacity of emergency mapping services.

Three-dimensional noise and spatial mapping system with aerial blimp robot

Three-dimensional noise and spatial mapping system with aerial blimp robot

Consistency in land‐cover mapping: Influence of field workers, spatial scale and classification system

AbstractQuestionsLand‐cover maps are used for nature management, but can they be trusted? This study addresses three questions: (1) what is the magnitude of between field worker inconsistencies in land‐cover maps and what may cause such inconsistencies; (2) in which ways and to what extent do spatial scale and mapping system influence inconsistencies between maps; and (3) are some biomes mapped more consistently than others, and if so, why?LocationGravfjellet, Øystre Slidre municipality, southern Norway.MethodsTwo different mapping systems, designed for mapping at different spatial scales, were used for parallel mapping by three different field workers, giving a total of six maps for the study area. Spatial consistency of the resulting maps was compared at two hierarchical levels for both systems.ResultsThe average pair‐wise spatial consistency at the highest hierarchical level was 83% for both systems, while the average pair‐wise spatial consistency at the lowest hierarchical level was 60.3% for the coarse system and 43.8% for the detailed system. Inconsistencies between maps were partly caused by the use of different land‐cover units and partly by spatial displacement.ConclusionsField workers made different maps despite using the same mapping systems, materials and methods. The differences were larger at lower hierarchical levels in the mapping systems and increased strongly with system complexity. Consistency among field workers should be estimated as a standard quality indicator in all field‐based mapping programmes.

Electrophysiological Signatures of Spatial Boundaries in the Human Subiculum.

Environmental boundaries play a crucial role in spatial navigation and memory across a wide range of distantly related species. In rodents, boundary representations have been identified at the single-cell level in the subiculum and entorhinal cortex of the hippocampal formation. Although studies of hippocampal function and spatial behavior suggest that similar representations might exist in humans, boundary-related neural activity has not been identified electrophysiologically in humans until now. To address this gap in the literature, we analyzed intracranial recordings from the hippocampal formation of surgical epilepsy patients (of both sexes) while they performed a virtual spatial navigation task and compared the power in three frequency bands (1-4, 4-10, and 30-90 Hz) for target locations near and far from the environmental boundaries. Our results suggest that encoding locations near boundaries elicited stronger theta oscillations than for target locations near the center of the environment and that this difference cannot be explained by variables such as trial length, speed, movement, or performance. These findings provide direct evidence of boundary-dependent neural activity localized in humans to the subiculum, the homolog of the hippocampal subregion in which most boundary cells are found in rodents, and indicate that this system can represent attended locations that rather than the position of one's own body.SIGNIFICANCE STATEMENT Spatial computations using environmental boundaries are an integral part of the brain's spatial mapping system. In rodents, border/boundary cells in the subiculum and entorhinal cortex reveal boundary coding at the single-neuron level. Although there is good reason to believe that such representations also exist in humans, the evidence has thus far been limited to functional neuroimaging studies that broadly implicate the hippocampus in boundary-based navigation. By combining intracranial recordings with high-resolution imaging of hippocampal subregions, we identified a neural marker of boundary representation in the human subiculum.

Single and Dual Photonic Jets and Corresponding Backscattering Enhancement With Tipped Waveguides: Direct Observation at Microwave Frequencies

This paper reports experiments on single and dual electromagnetic jets (also called photonic jets) emerging from a weakly multimode waveguide excited by a plane wave in the microwaves frequencies (30 GHz), ended with a tip with a special shape. The measurements are performed with a two-dimensional spatial field mapping system. This system acquires the electric field distribution at the end of the tipped waveguide. Qualitatively, the electric field maps confirm the presence of photonic jets that were recently predicted by a computational model based on boundary integral equations. Backscattering induced by the interaction of a particle with the electromagnetic jet is also measured; particles with a size smaller than the incident wavelength can be easily detected. The high sensitivity feature of the backscattering can be used to develop a near-field technique for microwave or optical imaging.

The hippocampus

The hippocampus

Place learning prior to and after telencephalon ablation in bamboo and coral cat sharks (Chiloscyllium griseum and Atelomycterus marmoratus)

This study assessed complex spatial learning and memory in two species of shark, the grey bamboo shark (Chiloscyllium griseum) and the coral cat shark (Atelomycterus marmoratus). It was hypothesized that sharks can learn and apply an allocentric orientation strategy. Eight out of ten sharks successfully completed the initial training phase (by locating a fixed goal position in a diamond maze from two possible start points) within 14.9±7.6sessions and proceeded to seven sets of transfer tests, in which sharks had to perform under altered environmental conditions. Transfer tests revealed that sharks had oriented and solved the tasks visually, using all of the provided environmental cues. Unintentional cueing did not occur. Results correspond to earlier studies on spatial memory and cognitive mapping in other vertebrates. Future experiments should investigate whether sharks possess a cognitive spatial mapping system as has already been found in several teleosts and stingrays. Following the completion of transfer tests, sharks were subjected to ablation of most of the pallium, which compromised their previously acquired place learning abilities. These results indicate that the telencephalon plays a crucial role in the processing of information on place learning and allocentric orientation strategies.

Mapping ideas from cyberspace to realspace: visualizing the spatial context of keywords from web page search results

We introduce a new method for visualizing and analyzing information landscapes of ideas and events posted on public web pages through customized web-search engines and keywords. This research integrates GIScience and web-search engines to track and analyze public web pages and their web contents with associated spatial relationships. Web pages searched by clusters of keywords were mapped with real-world coordinates (by geolocating their Internet Protocol addresses). The resulting maps represent web information landscapes consisting of hundreds of populated web pages searched by selected keywords. By creating a Spatial Web Automatic Reasoning and Mapping System prototype, researchers can visualize the spread of web pages associated with specific keywords, concepts, ideas, or news over time and space. These maps may reveal important spatial relationships and spatial context associated with selected keywords. This approach may provide a new research direction for geographers to study the diffusion of human thought and ideas. A better understanding of the spatial and temporal dynamics of the ‘collective thinking of human beings’ over the Internet may help us understand various innovation diffusion processes, human behaviors, and social movements around the world.

Direct observation of photonic jets and corresponding backscattering enhancement at microwave frequencies

We report the direct observation of photonic nanojets that emerged from the shadow side of a dielectric cylinder illuminated by plane waves in the microwave frequencies (8–13 GHz). Using our recently developed two-dimensional spatial field mapping system, we carried out a point-by-point measurement of both the phase and intensity of spatial electric field distribution inside and around scattering dielectric cylinders. The direct electric field maps confirm the subwavelength waist of the photonic jet. In addition, we also confirmed the superbackscattering enhancement induced by the presence of a particle much smaller than the initial focusing cylinder within the photonic jet.

Visual observation and quantitative measurement of the microwave absorbing effect at X band

We have set up a two-dimensional spatial field mapping system to measure graphically the quasi-free-space electromagnetic wave in a parallel plate waveguide. Our apparatus illustrates a potential application in characterizing the microwave absorbing materials. From the measured mappings of the microwave field, the visualization of spatial physical process and quantitative characterization of reflectivity coefficients can be achieved. This simple apparatus has a remarkable advantage over with conventional testing methods which usually involve huge, expensive anechoic chambers and demand samples of large size.

Blocking in human place learning: Evidence from virtual navigation

The associative conditioning phenomenon of blocking has recently been demonstrated in nonhuman place-learning paradigms, including the Morris water task (MWT). We demonstrate blocking in humans learning to place navigate in a computerized version of the MWT. Participants trained to locate an invisible goal with an initial set of distal cues were deficient in learning to locate the goal with a set of cues inserted later during training. This outcome is inconsistent with the spontaneous integration of novel environmental features into a unified spatial representation proposed by cognitive mapping theory (O’Keefe & Nadel, 1978) and suggests that error-correcting associative learning principles operate in the human spatial mapping system.

Multiple spatial learning strategies in goldfish (Carassius auratus)

There is a considerable amount of evidence that mammals and birds can use different spatial learning strategies based on multiple learning and memory systems. Unfortunately, only a few studies have investigated spatial learning and memory mechanisms in other vertebrates. This study aimed to identify the strategies used by goldfish to solve two different spatial tasks in a series of three experiments. In experiment 1, two groups of goldfish (Carassius auratus) were trained either in a spatial constancy task (SC), in which visual cues signalled the goal indirectly, or in a directly cued task (DC) in which similar cues signalled the goal directly. Transfer tests were conducted to study the effects of discrete cue deletion on the performance in both tasks. In these transfer tests the performance of the animals trained in the DC task dropped to chance level when the cue that signalled the goal directly was removed. In contrast, the removal of any single cue did not disrupt SC performance. In experiment 2, fish trained in the SC or the DC task were trained with the goal reversed. Goldfish in the SC group needed fewer sessions to master the reversal task than DC animals. Finally, experiment 3 investigated the effects of a substantial modification of the geometrical features of the apparatus on the performance of animals trained in the SC or in the DC condition. The performance of DC goldfish was not affected, whereas the same change disrupted performance in the SC animals despite the presence of the visual cues. These results suggest that there are separate spatial learning and memory systems in fish. Whereas the DC animals used a typical guidance strategy, relying only on the cue that signalled the goal directly, SC fish relied on a strategy with the properties of an actual spatial mapping system. Thus, the comparative approach points to the generality of these learning strategies among vertebrates.

The What-and-Where Filter: A Spatial Mapping Neural Network for Object Recognition and Image Understanding

The What-and-Where filter forms part of a neural network architecture for spatial mapping, object recognition, and image understanding. The Where filter responds to an image figure that has been separated from its background. It generates a spatial map whose cell activations simultaneously represent the position, orientation, and size of all the figures in a scene (where they are). This spatial map may be used to direct spatially localized attention to these image features. A multiscale array of oriented detectors, followed by competitive and interpolative interactions between position, orientation, and size scales, is used to define the Where filter. This analysis discloses several issues that need to be dealt with by a spatial mapping system that is based upon oriented filters, such as the role of cliff filters with and without normalization, the double peak problem of maximum orientation across size scale, and the different self-similar interpolation properties across orientation than across size scale. Several computationally efficient Where filters are proposed. The Where filter may be used for parallel transformation of multiple image figures into invariant representations that are insensitive to the figures' original position, orientation, and size. These invariant figural representations form part of a system devoted to attentive object learning and recognition (what it is). Unlike some alternative models where serial search for a target occurs, a What and Where representation can be used to rapidly search in parallel for a desired target in a scene. Such a representation can also be used to learn multidimensional representations of objects and their spatial relationships for purposes of image understanding. The What-and-Where filter is inspired by neurobiological data showing that a Where processing stream in the cerebral cortex is used for attentive spatial localization and orientation, whereas a What processing stream is used for attentive object learning and recognition.

Topographical disorientation

Abstract The literature on topographical disorientation is reviewed with respect to different types of spatial representation and modes of navigation. It is argued that there is not a strong case for the existence of separate representations for, on the one hand, the identity of environmental features, and, on the other hand, the location of environmental features relative to other landmarks. Identity and location may be considered more profitably as two aspects of one spatial mapping system, which encodes allocentric spatial relationships and permits landmark-based navigation. Egocentric spatial relationships, however, may also be important in navigation. It is argued that damage to the dorsal areas that are implicated in the updating and manipulation of egocentric reference frames, as well as damage to the allocentric system, may result in topographical disorientation.

Geographical information systems and tropical diseases

Geographical information systems and tropical diseases

Right-Left Confusion in Gerstmann' S Syndrome: A Model of Body Centered Spatial Orientation

Gerstmann's syndrome encompasses the tetrad of finger agnosia, agraphia, acalculia and right-left confusion and is associated with lesions of the dominant angular gyrus. The localizing value of this syndrome has been questioned because multiple mechanisms can account for each of the components of the syndrome. We present the case of a man who developed Gerstmann's syndrome following a focal infarct of the left angular gyrus. The patient's right-left confusion could not be accounted for by either an aphasia or a degraded body schema. A series of experiments that investigated the patient's spatial mapping system by progressively restricting the degrees of freedom for spatial rotation revealed an isolated defect in deriving the relative position of an object along the horizontal axis. Defective horizontal mapping can account for the other components of Gerstmann's syndrome because they all share a common dependency on relative horizontal positioning.

On the neural bases of the spatial mapping system: hippocampus vs. hippocampal formation.

As pointed out by Lynn Nadel in the lead article of this forum, since Thr Hippocumpus ns CI Cognitive M a p first appeared in 1978 many of the published studies have been concerned in some way with comparing the spatial mapping hypothesis with rival theoretical formulations. Basing their interpretations primarily on the results of lesion studies, investigators have suggested that the hippocampus is crucially involved in processes like working memory (Olton et al., 1979), the storage of intermediate-term memory (Rawlins, 1985), and configural associations ( Sutherland and Rudy, 1989). Why has it been so difficult to obtain convincing evidence 10 support one theory of hippocampal function to the exclusion of the others‘? While there are several reasons that could be given, most of them center around a failure on the part of many investigators to take into account the relevant neuroanatomy. Thus, one problem has been the confusion resulting from failing to always make a clear-cut distinction between the hippocampus and the hippocampal formation (see below). A second problem has been the variety of effects on behavior that are found when different structures and/or areas within the hippocampal formation are damaged. This is not surprising, since conventional lesion techniques (aTpiration, electrolytic, radio frequency) cause damage not only to cells in the area of interest, but usually to adjacent structures and the vasculature, as well as interrupt fibers of passage. In this essay, consideration will be given first to the relevant neuroanatomy. Selective hippocampal lesions obtained with neurotoxins will then be described. This will be followed by a brief description of the results obtained in a number of experiments designed to study the involvement of different components of the hippocampal formation in the processing of spatial information.

Real-time algorithms and data structures for underwater mapping

As part of the Multiple Autonomous Underwater Vehicle Project, a spatial mapping system has been developed to provide a model of the underwater environment suitable for autonomous navigation. The system is composed of multiresolution depth maps designed to integrate sensor data with an a priori model, an object/attribute database for storing information about detected objects, and a set of flags to monitor abnormal or emergency conditions in the environment. The structure of the mapping system and the algorithms used to map terrain and obstacles detected by acoustic sonar are described. >

Dissociation of the contributions of the prefrontal cortex and dorsomedial thalamic nucleus to spatially guided behavior in the rat

Rats with lesions of the medial frontal cortex or dorsomedial nucleus of the thalamus (MD) were studied in two spatial localization tasks: the Morris water task and the 8-arm radial arm maze. Rats with medial frontal lesions failed to learn to swim from different locations to a hidden platform located at a specific place in a large tank (Morris task) and were impaired at learning the location of reward in the radial arm maze. Rats with MD lesions were not impaired at spatial orientation in either task. The results provide the first unequivocal evidence of a spatial orientation deficit following frontal lesions and lend support to the notion that the frontal cortex forms part of a ‘spatial mapping system’. The results suggest that although MD is the major afferent to the frontal cortex, it does not provide necessary spatially-relevant input.

Précis of O'Keefe & Nadel'sThe hippocampus as a cognitive map

AbstractTheories of spatial cognition are derived from many sources. Psychologists are concerned with determining the features of the mind which, in combination with external inputs, produce our spatialized experience. A review of philosophical and other approaches has convinced us that the brain must come equipped to impose a three-dimensional Euclidean framework on experience – our analysis suggests that object re-identification may require such a framework. We identify this absolute, nonegocentric, spatial framework with a specific neural system centered in the hippocampus.A consideration of the kinds of behaviours in which such a spatial mapping system would be important is followed by an analysis of the anatomy and physiology of this system, with special emphasis on the place-coded neurons recorded in the hippocampus of freely moving rats. A tentative physiological model for the hippocampal cognitive map is proposed. A review of lesion studies, in tasks as diverse as discrimination learning, avoidance, and extinction, shows that the cognitive map notion can adequately explain much of the data.The model is extended to humans by the assumption that spatial maps are built in one hemisphere, semantic maps in the other. The latter provide a semantic deep structure within which discourse comprehension and production can be achieved. Evidence from the study of amnesic patients, briefly reviewed, is consistent with this extension.