From GeoVisualization to visual-analytics: methodologies and techniques for human-information discourse

2010 - 2011The objective of our research is to give support to decision makers when facing problems which require rapid solutions in spite of the complexity of scenarios under investigation. In order to achieve this goal our studies have been focused on GeoVisualization and GeoVisual Analytics research field, which play a relevant role in this scope, because they exploit results from several disciplines, such as exploratory data analysis and GIScience, to provide expert users with highly interactive tools by which they can both visually synthesize information from large datasets and perform complex analytical tasks. The research we are carrying out along this line is meant to develop software applications capable both to build an immediate overview of a scenario and to explore elements featuring it. To this aim, we are defining methodologies and techniques which embed key aspects from different disciplines, such as augmented reality and location-based services. Their integration is targeted to realize advanced tools where the geographic component role is primary and is meant to contribute to a human-information discourse... [edited by author]X n.s

Cartographic representation of spatiotemporal phenomena

Dissertação para obtenção do Grau de Mestre em Engenharia InformáticaThe field of geovisual analytics focuses on visualization techniques to analyze spatial data by enhancing human cognition. However, spatial data also has a temporal component that is practically disregarded when using conventional geovisual analytic tools. Some proposals have been made for techniques to analyze spatiotemporal data, but most were made for specific use cases, and are hard to abstract for other situations. There was a need to create a method to describe and compare the existing techniques. A catalog that provides a clear description of a set of techniques that deal with spatiotemporal data is proposed. This allows the identification of the most useful techniques depending on the required criteria. The description of a technique in the catalog relies on the two frameworks proposed. The first framework is used for describing spatiotemporal datasets resorting to data scenarios, a class of datasets. Twenty three data scenarios are described using this framework. The second framework is used for describing analytical tasks on spatiotemporal data, nine different tasks are described using this framework. Also, in this document, is the proposal of two new geovisual analytical techniques that can be applied to spatiotemporal data: the attenuation & accumulation map technique and the overlapping spatiotemporal windows technique. A prototype was developed that implements both techniques as a proof of concept.research project “GIAP - GeoInsight Analytics Platform (LISBOA-01-0202-FEDER- 024822)”, funded by Comissão de Coordenação e Desenvolvimento Regional de Lisboa e Vale do Tejo (PORLisboa), included in Sistema de Incentivos à Investigação e Desenvolvimento Tecnológico (SI I&DT), through a MSc research fellowship from FCT-UN

Map schematization with circular arcs

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

ESTUDO E REPRESENTAÇÃO COREMÁTICA

O enfoque deste artigo refere-será um estudo geográfico de variáveis intraurbana, que objetivou contribuir para um entendimento mais aprofundado sobre o processo de produção do espaço, através de uma análise realizada para a cidade de Paulínia (SP). Para representação cartográfica de variáveis intraurbanas, a coremática mostrou-se apropriada para exposição dos principais processos urbanos, sobretudo por produzir uma comunicação mais objetiva, direcionada e auxiliar numa reflexão articulada de suporte às práticas mais efetivas de planejamento e gestão municipa

Enhancing Exploratory Analysis across Multiple Levels of Detail of Spatiotemporal Events

Crimes, forest fires, accidents, infectious diseases, human interactions with mobile devices (e.g., tweets) are being logged as spatiotemporal events. For each event, its spatial location, time and related attributes are known with high levels of detail (LoDs). The LoD of analysis plays a crucial role in the user’s perception of phenomena. From one LoD to another, some patterns can be easily perceived or different patterns may be detected, thus requiring modeling phenomena at different LoDs as there is no exclusive LoD to study them. Granular computing emerged as a paradigm of knowledge representation and processing, where granules are basic ingredients of information. These can be arranged in a hierarchical alike structure, allowing the same phenomenon to be perceived at different LoDs. This PhD Thesis introduces a formal Theory of Granularities (ToG) in order to have granules defined over any domain and reason over them. This approach is more general than the related literature because these appear as particular cases of the proposed ToG. Based on this theory we propose a granular computing approach to model spatiotemporal phenomena at multiple LoDs, and called it a granularities-based model. This approach stands out from the related literature because it models a phenomenon through statements rather than just using granules to model abstract real-world entities. Furthermore, it formalizes the concept of LoD and follows an automated approach to generalize a phenomenon from one LoD to a coarser one. Present-day practices work on a single LoD driven by the users despite the fact that the identification of the suitable LoDs is a key issue for them. This PhD Thesis presents a framework for SUmmarizIng spatioTemporal Events (SUITE) across multiple LoDs. The SUITE framework makes no assumptions about the phenomenon and the analytical task. A Visual Analytics approach implementing the SUITE framework is presented, which allow users to inspect a phenomenon across multiple LoDs, simultaneously, thus helping to understand in what LoDs the phenomenon perception is different or in what LoDs patterns emerge

Cognitive Foundations for Visual Analytics

In this report, we provide an overview of scientific/technical literature on information visualization and VA. Topics discussed include an update and overview of the extensive literature search conducted for this study, the nature and purpose of the field, major research thrusts, and scientific foundations. We review methodologies for evaluating and measuring the impact of VA technologies as well as taxonomies that have been proposed for various purposes to support the VA community. A cognitive science perspective underlies each of these discussions

Visualização cartográfica assistida num ambiente SOLAP

Dissertação para obtenção do Grau de Mestre em Engenharia InformáticaO conceito Spatial OLAP introduz a visualização cartográfica nos sistemas Business Intelligent/OLAP. Esta tem grandes potencialidades para melhorar a análise de grandes quantidades de dados georreferenciados e o respetivo processo de tomada de decisão. O potencial que é possível obter da visualização cartográfica depende fortemente do uso apropriado não só das variáveis visuais como também de outros elementos que possam ser utilizados para representar informação no mapa (ex.: gráficos). Porém, num ambiente SOLAP, o analista deveria estar apenas focado em procurar informação útil abstraindo-se de como deve ser construída uma visualização cartográfica adequada. Neste trabalho, é proposto um modelo para assistir o utilizador na construção de visualizações cartográficas. O modelo proposto considera: (i) a meta-informação existente sobre os modelos multidimensionais; (ii) a interrogação realizada; (iii) os dados resultantes. Através do modelo proposto, pretende-se assistir o utilizador na construção de mapas temáticos apropriados. Neste trabalho é proposto: (i) um modelo para descrever tipos de visualização; (ii) um modelo para descrever o contexto analítico SOLAP; (iii) uma metodologia para a seleção adequada dos tipos de visualização aplicáveis em cada contexto analítico SOLAP e sua instanciação. O modelo de cartografia assistida em ambiente SOLAP proposto neste trabalho foi implementado sobre protótipo SOLAP+