166 research outputs found

    Interactive Visualisation of Hierarchical Quantitative Data: An Evaluation

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    We have compared three common visualisations for hierarchical quantitative data, treemaps, icicle plots and sunburst charts as well as a semicircular variant of sunburst charts we call the sundown chart. In a pilot study, we found that the sunburst chart was least preferred. In a controlled study with 12 participants, we compared treemaps, icicle plots and sundown charts. Treemap was the least preferred and had a slower performance on a basic navigation task and slower performance and accuracy in hierarchy understanding tasks. The icicle plot and sundown chart had similar performance with slight user preference for the icicle plot.Comment: Presented at IEEE VIS 2019 in Vancouver, Canada and included in the VIS 2019 conference proceedings. Improved the image quality in the pape

    Combining Extended Table Lens and Treemap Techniques for Visualizing Tabular Data

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    Combining Extended Table Lens and Treemap Techniques for Visualizing Tabular Data

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    Combining Extended Table Lens and Treemap Techniques for Visualizing Tabular Data

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    Temporal Treemaps for Visualizing Time Series Data

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    Treemap is an interactive graphical technique for visualizing large hierarchical information spaces using nested rectangles in a space filling manner. The size and color of the rectangles show data attributes and enable users to spot trends, patterns or exceptions. Current implementations of treemaps help explore time-invariant data. However, many real-world applications require monitoring hierarchical, time-variant data. This thesis extends treemaps to interactively explore time series data by mapping temporal changes to color attribute of treemaps. Specific contributions of this thesis include: · Temporal treemaps for exploring time series data through visualizing absolute or relative changes, animating them over time, filtering data items, and discovering trends using time series graphs. · The design and implementation of extensible software modules based on systems engineering methodologies and object-oriented approach. · Validation through five case studies: health statistics, web logs, production data, birth statistics, and help-desk tickets; future improvements identified from the user feedback

    Using Treemaps to Visualize Threaded Discussion Forums on PDAs

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    This paper describes a new way of visualizing threaded discussion forums on compact displays. The technique uses squarified treemaps to render the threads in discussion forums as colored rectangles, thereby using 100% of the limited screen space. We conducted a preliminary user study, which compared the treemap version and a traditional text based tree interface. This showed that the contents of the discussion forum were easily grasped when using a treemap, even though there were in excess of one hundred threads. In particular our technique showed a significant improvement in time for finding the largest and most active threads. Overall, it was shown that the benefits derived from using treemaps on desktop computers are still valid for small screens

    Space Partitioning Schemes and Algorithms for Generating Regular and Spiral Treemaps

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    Treemaps have been widely applied to the visualization of hierarchical data. A treemap takes a weighted tree and visualizes its leaves in a nested planar geometric shape, with sub-regions partitioned such that each sub-region has an area proportional to the weight of its associated leaf nodes. Efficiently generating visually appealing treemaps that also satisfy other quality criteria is an interesting problem that has been tackled from many directions. We present an optimization model and five new algorithms for this problem, including two divide and conquer approaches and three spiral treemap algorithms. Our optimization model is able to generate superior treemaps that could serve as a benchmark for comparing the quality of more computationally efficient algorithms. Our divide and conquer and spiral algorithms either improve the performance of their existing counterparts with respect to aspect ratio and stability or perform competitively. Our spiral algorithms also expand their applicability to a wider range of input scenarios. Four of these algorithms are computationally efficient as well with quasilinear running times and the last algorithm achieves a cubic running time. A full version of this paper with all appendices, data, and source codes is available at \anonymizeOSF{\OSFSupplementText}

    E XPLORING DIFFERENCES IN MULTIVARIATE DATASETS USING HIERARCHIES AN INTERACTIVE INFORMATION VISUALIZATION APPROACH

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    Hierarchies are a useful way of representing data. The parent-child relationships they define facilitate the analysis of a dataset by breaking it down into its component parts. Representing data as hierarchies can also be used to track changes to a dataset over time or between versions. For example, analysts can use hierarchies to uncover changes in the US Federal Budget in the last twenty years, by grouping accounts by Agencies and Bureaus. Similarly, a company manager can analyze changes to their product sales due to the holiday season by breaking them up by markets and product categories. Exploring differences in such trees could help them understand changes in the data. However, comparing hierarchies is a difficult task, even when comparing two trees with a small number of nodes. To address this, information visualization techniques were used to support data comparison tasks using hierarchies. After evaluating my techniques with domain experts on real world problems, I identified and addressed two main research topics: Abstract This dissertation first tackled the problem of comparing two versions of a tree by using two types of change, while most of the significant work on this topic has focused only on changes in node values or changes in topology. TreeVersity (http://hcil.cs.umd.edu/treeversity) is a comparison tool that allows users to explore changes between two versions of a tree by tracking node value differences, and newly created or removed nodes. Domain experts using TreeVersity were excited to discover differences in the trees, but expressed a desire to explore the evolution of a dataset over time. To that end, they suggested applying TreeVersity comparison capabilities to datasets that were non inherently hierarchical. Abstract Following users' feedback, the problem of exploring changes over time in datasets that can be categorized as trees was addressed next. TreeVersity2 (http://treeversity.cattlab.umd.edu is a web-based data comparison tool that allows users to explore a tree that changes over time and of datasets that are not inherently hierarchical, by categorizing them by their attributes. TreeVersity2 also helps users navigate the sometimes large amounts of differences between versions of a tree using an interactive textual reporting tool. Abstract My research has resulted in three main contributions: First, the introduction of the Bullet, a visualization glyph to represent four characteristics of change (as described in Section 1.2) in tree nodes, and the implementation of the Bullet in TreeVersity. Second, the creation of the StemView, a tree visualization technique that represents five characteristics of change in all the nodes of a tree (not just the leaves), and the implementation of the StemView in TreeVersity2. Furthermore, my research resulted in the development of the reporting tool, another feature of TreeVersity2, which helps users navigate outstanding changes in the tree with textual representations and coordinated interactions. Third, the development of 13 case studies with domain experts on real world comparison problems. The case studies have validated the utility and flexibility of my approaches. Finally, my research opens possibilities for future research on comparing hierarchical structures
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