464 research outputs found

    Exploring Curved Schematization of Territorial Outlines

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    Map schematization with circular arcs

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    We present an algorithm to compute schematic maps with circular arcs. Our algorithm iteratively replaces two consecutive arcs with a single arc to reduce the complexity of the output map and thus to increase its level of abstraction. Our main contribution is a method for replacing arcs that meet at high-degree vertices. This allows us to greatly reduce the output complexity, even for dense networks. We experimentally evaluate the effectiveness of our algorithm in three scenarios: territorial outlines, road networks, and metro maps. For the latter, we combine our approach with an algorithm to more evenly distribute stations. Our experiments show that our algorithm produces high-quality results for territorial outlines and metro maps. However, the lack of caricature (exaggeration of typical features) makes it less useful for road networks

    Algorithms for curved schematization

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    How human schematization and systematic errors take effect on sketch map formalizations

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    Dissertation submitted in partial fulfilment of the requirements for the Degree of Master of Science in Geospatial TechnologiesSketch map is an important way to represent spatial information used in many geospatial reasoning tasks (Forbus, K., Usher, J., & Chapman, V. 2004). Compared with verbal or textual language, sketch map is a more interactive mode that more directly supports human spatial thinking and thus is a more natural way to reflect how people perceive properties of spatial objects and their spatial relations. One challenging application of sketch maps is called Spatial-Query-by-Sketch proposed by Egenhofer. Being a design of query language for geographic information systems (GISs), it allows a user to formulate a spatial query by drawing the desired spatial configuration with a pen on a touch-sensitive computer screen and get it translated into a symbolic representation to be processed against a geographic database (Egenhofer, M. 1997). During the period of sketch map drawing, errors due to human spatial cognition in mind may occur. A ready example is as follows: distance judgments for route are judged longer when the route has many turns or landmarks or intersections (Tversky, B. 2002). Direction get straightened up in memory. When Parisians were asked to sketch maps of their city, the Seine was drawn as a curve, but straighter than it actually is (Milgram, S. and Jodelet, D. 1976). Similarly, buildings and streets with different shapes are often simply depicted as schematic figures like blobs and lines. These errors are neither random nor due solely to ignorance; rather they appear to be a consequence of ordinary perceptual and cognitive processes (Tversky, 2003). Therefore, when processing sketch map analysis and representing it in a formal way, like Egenhofer's analysis approach for Spatial-Query-by-Sketch, the resulting formalization must necessarily be wrong if it does not account for the fact that some spatial information is distorted or omitted by humans. Therefore, when sketch map analysis is processed and represented in a formal way same as Egenhofer’s analytical approach to Spatial-Query-by-Sketch, the resulting formalization is simply erroneous since it never takes into account the fact that some spatial information is distorted or neglected in human perceptions. Though Spatial-Query-by-Sketch overcomes the limitations of conventional spatial query language by taking into consideration those alternative interaction methods between users and data, it is still not always true that accuracy of its query results is reliable.(...

    Similarity measures and algorithms for cartographic schematization

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    DNA Mutations via Chern-Simons Currents

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    We test the validity of a possible schematization of DNA structure and dynamics based on the Chern-Simons theory, that is a topological field theory mostly considered in the context of effective gravity theories. By means of the expectation value of the Wilson Loop, derived from this analogue gravity approach, we find the point-like curvature of genomic strings in KRAS human gene and COVID-19 sequences, correlating this curvature with the genetic mutations. The point-like curvature profile, obtained by means of the Chern-Simons currents, can be used to infer the position of the given mutations within the genetic string. Generally, mutations take place in the highest Chern-Simons current gradient locations and subsequent mutated sequences appear to have a smoother curvature than the initial ones, in agreement with a free energy minimization argument
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