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Quality online maps and mapping resources, while indispensable to library users, can be challenging to locate. The range of available map types continues to expand and includes road maps, historical collections, political and phys...
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Quality online maps and mapping resources, while indispensable to library users, can be challenging to locate. The range of available map types continues to expand and includes road maps, historical collections, political and physical atlases as well as maps and images of the moon and certain planets. Interactive mapping sites continue to grow and provide unique opportunities for users to interact with socio-economic, historic and physical data while creating unique and personalized maps. This article serves to highlight the best online resources for both map image collections and interactive mapping sites found on the Internet today.
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This study analyses the impact that different rhetorical styles have on reader trust in, fondness for and memory of maps showing the same exact data. Previous research has identified four unique rhetorical styles used on maps mean...
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This study analyses the impact that different rhetorical styles have on reader trust in, fondness for and memory of maps showing the same exact data. Previous research has identified four unique rhetorical styles used on maps meant to persuade an audience. Four maps of a hypothetical nuclear meltdown in the USA using embellished radiation data were produced, each following the design guidelines of one of the four rhetorical styles. An online survey was created testing: (1) map readers' inclination to believe the data being shown on the four maps; (2) the impact the representations had on personal views regarding nuclear power; (3) map reader trust in the maps; (4) fondness for the maps; and (5) memorability of the maps (i.e. how likely a map would be recalled). The results indicate that different map rhetorical styles result in different levels of opinion change, trust in the data and confidence in answering questions about the data. Designing convincing arguments with maps requires more than lying; different rhetorical designs can help achieve different persuasive goals.
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Topological maps are often used in robotics. This paper presents a novel topological map representation, the Area Graph, and how to extract it from 2D grid maps. This representation is then utilized for map matching, which we pres...
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Topological maps are often used in robotics. This paper presents a novel topological map representation, the Area Graph, and how to extract it from 2D grid maps. This representation is then utilized for map matching, which we present in two variants. Experiments are presented which evaluate these methods and explore the effects of the important parameters. The Area Graph generation algorithm is based on the Voronoi Diagram (VD), which is filtered and pruned to get the Topology Graph. During this process, the faces of the regions are maintained and then used as the areas of the Area Graph, which is then post-processed with a room detection step to avoid over-segmentation. The map matching is utilizing extracted features from the Area Graph and also using the neighborhood information encoded in it to find matching areas. The results of the experiments show that the Area Graph generation algorithm outperforms the other methods in terms of accuracy. Additionally, our matching algorithm is superior to image-based as well as state of the art map matching approaches.
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In this note we show that a harmonic quasiconformal mapping f = u + iv with respect to the Poincare metric of the upper half plane R-+(2) onto itself such that v(x, y) = v(y) or u(x, y) = u(x) is a conformal mapping. (C) 2008 Else...
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In this note we show that a harmonic quasiconformal mapping f = u + iv with respect to the Poincare metric of the upper half plane R-+(2) onto itself such that v(x, y) = v(y) or u(x, y) = u(x) is a conformal mapping. (C) 2008 Elsevier Inc. All rights reserved.
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In this paper, a novel grayscale image cryptosystem based on hybrid chaotic maps is proposed. The scheme employs both confusion phase to scramble the location of pixels and diffusion phase for changing the content of pixels in con...
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In this paper, a novel grayscale image cryptosystem based on hybrid chaotic maps is proposed. The scheme employs both confusion phase to scramble the location of pixels and diffusion phase for changing the content of pixels in consecutive manner. In this scheme, Arnold's cat map is introduced to perform confusion operation and the principle of diffusion is achieved by using the proper selection of combined Sine map, Logistic map, and Tent map. Furthermore, exclusive OR (XOR), exchange, and transform operations are used to enhance the efficiency of diffusion phase. Accordingly, the use of chaotic maps and XOR operation provides a dual layer of security. Depending on the average absolute value of horizontal, vertical, and diagonal correlation coefficient of plain image as well as bifurcation properties of chaotic maps, one of the mentioned chaotic maps is selected for diffusion phase. First, original gray scale image matrix is extended to square matrix by adding the sequences generated with proper chaotic maps to implement the first step of diffusion phase. Then the Arnold's cat map changes pixels location of new extended matrix by means of certain equation as confusion phase. The encrypted image is generated after applying XOR, exchange and transform operations on the content of pixels as second step of diffusion phase. Thus the system is able to build several more complicated chaotic structures. In addition the encryption and decryption processing time directly depend on the value of correlation coefficient of original image. Plain images with less correlation coefficient have less encryption and decryption processing time, and vice versa. Compared with several existing methods, the proposed scheme has more better properties, including wider chaotic ranges and more complex chaotic behavior. Experimental results show that the proposed system has proper encryption and decryption processing time, unified average changing intensity (UACI), number of pixel change rate (NPCR), and extensive security analysis for kind of images.
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Maps have been one of the greatest constants of my sometimes fickle life. They were there as far back as I can remember, luring me in as a child with their bright, bold representation of the world around me. They have followed me ...
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Maps have been one of the greatest constants of my sometimes fickle life. They were there as far back as I can remember, luring me in as a child with their bright, bold representation of the world around me. They have followed me on my travels and in my career, through life in Kidderminster, London, Cambridge, Birmingham and then out into the wilds of mid Wales. I have loved them fiercely, and will do so till the end.
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We give a construction of completely integrable four-dimensional Hamiltonian systems with cubic Hamilton functions. Applying to the corresponding pairs of commuting quadratic Hamiltonian vector fields the so called Kahan-Hirota-Ki...
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We give a construction of completely integrable four-dimensional Hamiltonian systems with cubic Hamilton functions. Applying to the corresponding pairs of commuting quadratic Hamiltonian vector fields the so called Kahan-Hirota-Kimura discretization scheme, we arrive at pairs of birational four-dimensional maps. We show that these maps are symplectic with respect to a symplectic structure that is a perturbation of the standard symplectic structure on R-4, and possess two independent integrals of motion, which are perturbations of the original Hamilton functions and which are in involution with respect to the perturbed symplectic structure. Thus, these maps are completely integrable in the Liouville-Arnold sense. Moreover, under a suitable normalization of the original pairs of vector fields, the pairs of maps commute and share the invariant symplectic structure and the two integrals of motion.
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Chaotic behavior is a term that is attributed to dynamical systems whose solutions are highly sensitive to initial conditions. This means that small perturbations in the initial conditions can lead to completely different trajecto...
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Chaotic behavior is a term that is attributed to dynamical systems whose solutions are highly sensitive to initial conditions. This means that small perturbations in the initial conditions can lead to completely different trajectories in the solution space. These types of chaotic dynamical systems arise in various natural or artificial systems in biology, meteorology, economics, electrical circuits, engineering, computer science and more. Of these innumerable chaotic systems, perhaps the most interesting are those that exhibit attracting behavior. By that, the authors refer to systems whose trajectories converge with time to a set of values, called an attractor. This can be a single point, a curve or a manifold. The attractor is called strange if it is a set with fractal structure. Such systems can be both continuous and discrete. This paper reports on some new chaotic discrete time two dimensional maps that are derived from simple modifications to the well-known Henon, Lozi, Sine-sine and Tinkerbell maps. Numerical simulations are carried out for different parameter values and initial conditions and it is shown that the mappings either diverge to infinity or converge to attractors of many different shapes.
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In this paper, we tackle the problem of generalizing conformal maps to volumetric meshes. Current methods seek for harmonicity but unfortunately, no computational methods optimize conformality in the volumetric context. As it is p...
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In this paper, we tackle the problem of generalizing conformal maps to volumetric meshes. Current methods seek for harmonicity but unfortunately, no computational methods optimize conformality in the volumetric context. As it is proven that conformal maps do not exist for general volume transformations, we seek to optimize shape preservation with a generalization of the Cauchy-Riemann equations. Our algorithm is fast and easily adaptable to existing harmonic mapping methods. Compared to harmonic maps, results show improvements on both angular and volumetric energy measures at a cost below 1% of total computations. The method extends well in any dimension and several research areas could benefit from our derivations of volumetric conformal optimization.
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Despite their status and ubiquity, modern state topographic maps are seldom the topic of cartographic research. There is a notable deficiency in the number of empirical studies that investigate their design, or, given their herita...
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Despite their status and ubiquity, modern state topographic maps are seldom the topic of cartographic research. There is a notable deficiency in the number of empirical studies that investigate their design, or, given their heritage, examine their symbology with a view to identifying the ingredients of style. The issue of stylistic similarities and differences raises important questions for the history and development of map symbology and the wider relationship between maps and society. The absence of critical interpretations of topographic map symbology-which lay beyond a discussion of the problems of cartographic representation-has also meant that the cultural rationale for stylistic diversity has been neglected. This paper describes a strategy for identifying and explaining similarities and differences in the cartographic style of topographic maps, with a view toward developing a methodology for classifying and analyzing their symbology. It provides a review of existing approaches for investigating style in thematic cartography (such as transport maps and national atlases) before proposing that a future method should be based on that of Piket (1972), and offer direct application. A systematic analysis of topographic map symbology would be particularly useful for identifying supranational styles and for exploring the extent to which national conditions-specific variables such as population density and cars in use, together with wider ideological changes such as the achievement of political independence-are intrinsically expressed through topographic map symbology.
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