Rethinking Map Legends with Visualization

This design paper presents new guidance for creating map legends in a dynamic environment. Our contribution is a set of guidelines for legend design in a visualization context and a series of illustrative themes through which they may be expressed. These are demonstrated in an applications context through interactive software prototypes. The guidelines are derived from cartographic literature and in liaison with EDINA who provide digital mapping services for UK tertiary education. They enhance approaches to legend design that have evolved for static media with visualization by considering: selection, layout, symbols, position, dynamism and design and process. Broad visualization legend themes include: The Ground Truth Legend, The Legend as Statistical Graphic and The Map is the Legend. Together, these concepts enable us to augment legends with dynamic properties that address specific needs, rethink their nature and role and contribute to a wider re-evaluation of maps as artifacts of usage rather than statements of fact. EDINA has acquired funding to enhance their clients with visualization legends that use these concepts as a consequence of this work. The guidance applies to the design of a wide range of legends and keys used in cartography and information visualization

Using treemaps for variable selection in spatio-temporal visualisation

We demonstrate and reflect upon the use of enhanced treemaps that incorporate spatial and temporal ordering for exploring a large multivariate spatio-temporal data set. The resulting data-dense views summarise and simultaneously present hundreds of space-, time-, and variable-constrained subsets of a large multivariate data set in a structure that facilitates their meaningful comparison and supports visual analysis. Interactive techniques allow localised patterns to be explored and subsets of interest selected and compared with the spatial aggregate. Spatial variation is considered through interactive raster maps and high-resolution local road maps. The techniques are developed in the context of 42.2 million records of vehicular activity in a 98 km(2) area of central London and informally evaluated through a design used in the exploratory visualisation of this data set. The main advantages of our technique are the means to simultaneously display hundreds of summaries of the data and to interactively browse hundreds of variable combinations with ordering and symbolism that are consistent and appropriate for space- and time- based variables. These capabilities are difficult to achieve in the case of spatio-temporal data with categorical attributes using existing geovisualisation methods. We acknowledge limitations in the treemap representation but enhance the cognitive plausibility of this popular layout through our two-dimensional ordering algorithm and interactions. Patterns that are expected (e.g. more traffic in central London), interesting (e.g. the spatial and temporal distribution of particular vehicle types) and anomalous (e.g. low speeds on particular road sections) are detected at various scales and locations using the approach. In many cases, anomalies identify biases that may have implications for future use of the data set for analyses and applications. Ordered treemaps appear to have potential as interactive interfaces for variable selection in spatio-temporal visualisation. Information Visualization (2008) 7, 210-224. doi: 10.1057/palgrave.ivs.950018

Métodos para melhora da análise visual de redes em fluxo contínuo de dados

Temporal networks (also known as dynamic networks) are often used to model connections that occur over time between parts of a system by using nodes and edges. In temporal networks, all nodes, edges, and times, are known and available to be used in the analysis. However, in several real-world applications, data are produced in a massive and continuous way, which is known as data stream. In this case, the volume of data may be so large that the storage may be impossible and mining tasks become more challenging. In streaming temporal networks, edges are continuously arriving in non-stationary distribution. In both temporal and streaming temporal networks, patterns related to node and edge activity are typically irregular in time, which makes the visualization of such networks helpful to gain insights about network structure and dynamics. Nevertheless, the non-stationary distribution of incoming data increases complexity and turns the streaming temporal network visualization even more challenging. Several visualization layouts have been proposed, but they all have limitations. The main challenge in this context is the amount of visual information, that increases depending on the network size and density, and causes visual clutter due to edge overlap, fine temporal resolution, and node proximity. In this thesis, we propose methods to enhance the visualization of streaming temporal networks through the manipulation of the three network dimensions, namely node, edge, and time. Specifically, we propose: (i) CNO, a visual scalable node ordering method; (ii) SEVis, a streaming edge sampling method; and (iii) a streaming method that adapts the temporal resolution according to local levels of node activity. We also present a comparative study considering the combination of these methods. We show through case studies with real-world networks that each of these methods greatly improves layout readability, thus leading to a fast and reliable decision making.CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorTese (Doutorado)Redes temporais (ou dinâmicas) são frequentemente usadas para modelar conexões que ocorrem ao longo do tempo entre partes de um sistema por meio de nós e arestas. Nessas redes, todos os nós, arestas e instantes de tempo são conhecidos e estão disponíveis para serem utilizados na análise. Entretanto, em várias situações reais, dados são produzidos de forma massiva e contínua, o que é conhecido como fluxo contínuo de dados (FCD). Nesse tipo de aplicação, o volume de dados pode ser tão grande que o armazenamento deles pode ser impossível e as tarefas de mineração se tornam ainda mais desafiadoras. Em redes provenientes de FCD, arestas são continuamente adicionadas em distribuição não-estacionária. Tanto em redes temporais quanto em redes em FCD, padrões relacionados à atividade de nós e arestas são tipicamente irregulares ao longo do tempo, o que torna a visualização dessas redes útil para obter insights sobre a estrutura e dinâmica delas. Por outro lado, a distribuição não-estacionária aumenta a complexidade e torna a visualização de redes em FCD ainda mais desafiadora. Vários layouts visuais foram propostos até hoje, mas todos possuem limitações. O principal desafio é a quantidade de informação visual, que aumenta dependendo do tamanho e densidade da rede e causa poluição visual devido à sobreposição de arestas, resolução temporal e proximidade dos nós. Nesta tese, nós propomos métodos para melhorar a visualização de redes em FCD por meio da manipulação das três dimensões da rede: nó, aresta e tempo. Mais especificamente, nós propomos: (i) CNO, um método de ordenação de nós visualmente escalável; (ii) SEVis, um método de amostragem de arestas em FCD; (iii) um método para FCD que adapta a resolução temporal de acordo com níveis locais de atividade de nós. Também apresentamos um estudo comparativo considerando a combinação destes métodos. Por meio de estudos de caso com redes reais, mostramos que cada um dos métodos melhora bastante a legibilidade do layout, levando a uma tomada de decisão rápida e confiável

Spatial Decision Support System for Student Data: A Case Study of Yemen

This study aims to examine the effectiveness of using Geographic Information System (GIS) technology to create a geospatially-enabled student data management system (SDMS). Although there are many applications available to create SDMS, GIS has some unique features that would make managing student data more convenient. This research gap was identified via stakeholder interaction and systematic literature review where no current geospatially-enabled SDMS was discovered that utilizes GIS technology to accommodate and share the information between multi-stakeholders. As such, this research aims to utilize GIS and visualization tools to design and implement Geospatial SDMS that help different stakeholders, such as scholarship organizations, employers, and students to speed and improve their decision outcomes. The project is based on a case study in Yemen. Using a qualitative assessment method, this system was evaluated in a real-world scenario where different stakeholders were introduced to the system and their feedback was collected via a focus group

Survey on Individual Differences in Visualization

Developments in data visualization research have enabled visualization systems to achieve great general usability and application across a variety of domains. These advancements have improved not only people's understanding of data, but also the general understanding of people themselves, and how they interact with visualization systems. In particular, researchers have gradually come to recognize the deficiency of having one-size-fits-all visualization interfaces, as well as the significance of individual differences in the use of data visualization systems. Unfortunately, the absence of comprehensive surveys of the existing literature impedes the development of this research. In this paper, we review the research perspectives, as well as the personality traits and cognitive abilities, visualizations, tasks, and measures investigated in the existing literature. We aim to provide a detailed summary of existing scholarship, produce evidence-based reviews, and spur future inquiry

Information Exchange Decision Support (IEDS) Framework

Information Exchange (IE) is an important area of research in Information Systems (IS), there is a lack of a framework that guides the design of an IE systems to support IE among multiple stakeholders with the purpose of improving the decision-making. To address this literature gap, this paper utilizes the Theory of Information Exchange (ToIE) as a kernel theory to develop an Information Exchange Decision Support (IEDS) framework. The framework depicts how to design an IE platform for multiple stakeholders to improve their decision quality. The qualitative evaluation shows that the IEDS framework is useful for identifying stakeholders, specifying information to be exchanged, and maintaining motivation factors necessary for IE. The IEDS framework offers prescriptive knowledge for building an effective IE in a multiple stakeholder environment and it can be applied in different business domains and provide guidance to the designers and developers of IE platforms

Toward Systematic Design Considerations of Organizing Multiple Views

Multiple-view visualization (MV) has been used for visual analytics in various fields (e.g., bioinformatics, cybersecurity, and intelligence analysis). Because each view encodes data from a particular perspective, analysts often use a set of views laid out in 2D space to link and synthesize information. The difficulty of this process is impacted by the spatial organization of these views. For instance, connecting information from views far from each other can be more challenging than neighboring ones. However, most visual analysis tools currently either fix the positions of the views or completely delegate this organization of views to users (who must manually drag and move views). This either limits user involvement in managing the layout of MV or is overly flexible without much guidance. Then, a key design challenge in MV layout is determining the factors in a spatial organization that impact understanding. To address this, we review a set of MV-based systems and identify considerations for MV layout rooted in two key concerns: perception, which considers how users perceive view relationships, and content, which considers the relationships in the data. We show how these allow us to study and analyze the design of MV layout systematically.Comment: Short paper with 4 pages + 1 reference page, 2 figures, 1 table, accepted at IEEE VIS 2022 conferenc

Interactive Visualization for Deep Organizational data

During the last decade, there has been a growing interest in investigating how and why people use organizational data to solve problems, make decisions, and perform other cognitive activities, especially in the social network, healthcare, and education domains. Working with organizational data is challenging because of the complex and multi-structured nature of it. One way to support cognitive activities with organizational data is through the use of interactive visualization tools that provide different representations and mechanisms for interacting with deep layers of the data. In this research, we have deep organizational data which is mainly about collaborations inside universities. The thesis goal is making an interactive visualization tool to support complex cognitive activities with this database. The generated visualization tool has an expandable and reusable structure as well as innovative representations and interactions designed to allow navigating through the data intuitively