Browsing by Author "Mchedlidze, Tamara"

Now showing 1 - 3 of 3
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    An Experimental Evaluation of Viewpoint-Based 3D Graph Drawing
    (The Eurographics Association and John Wiley & Sons Ltd., 2024) Wageningen, Simon van; Mchedlidze, Tamara; Telea, Alexandru; Aigner, Wolfgang; Archambault, Daniel; Bujack, Roxana
    Node-link diagrams are a widely used metaphor for creating visualizations of relational data. Most frequently, such techniques address creating 2D graph drawings, which are easy to use on computer screens and in print. In contrast, 3D node-link graph visualizations are far less used, as they have many known limitations and comparatively few well-understood advantages. A key issue here is that such 3D visualizations require users to select suitable viewpoints. We address this limitation by studying the ability of layout techniques to produce high-quality views of 3D graph drawings. For this, we perform a thorough experimental evaluation, comparing 3D graph drawings, rendered from a covering sampling of all viewpoints, with their 2D counterparts across various state-of-the-art node-link drawing algorithms, graph families, and quality metrics. Our results show that, depending on the graph family, 3D node-link diagrams can contain a many viewpoints that yield 2D visualizations that are of higher quality than those created by directly using 2D node-link diagrams. This not only sheds light on the potential of 3D node-link diagrams but also gives a simple approach to produce high-quality 2D node-link diagrams.
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    Identifying Cluttering Edges in Near-Planar Graphs
    (The Eurographics Association, 2023) Wageningen, Simon van; Mchedlidze, Tamara; Telea, Alexandru; Hoellt, Thomas; Aigner, Wolfgang; Wang, Bei
    Planar drawings of graphs tend to be favored over non-planar drawings. Testing planarity and creating a planar layout of a planar graph can be done in linear time. However, creating readable drawings of nearly planar graphs remains a challenge. We therefore seek to answer which edges of nearly planar graphs create clutter in their drawings generated by mainstream graph drawing algorithms. We present a heuristic to identify problematic edges in nearly planar graphs and adjust their weights in order to produce higher quality layouts with spring-based drawing algorithms. Our experiments show that our heuristic produces significantly higher quality drawings for augmented grid graphs, augmented triangulations, and deep triangulations.
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    Metaphoric Maps for Dynamic Vertex-weighted Graphs
    (The Eurographics Association, 2022) Mchedlidze, Tamara; Schnorr, Christian; Agus, Marco; Aigner, Wolfgang; Hoellt, Thomas
    In this paper we study metaphoric maps of dynamic vertex-weighted graphs. Dynamic operations on such graphs allow a vertex to change the weight, vertices and edges appear and disappear. In the metaphoric map this is viewed as country shrink and growth, appearance and disappearance and change in the country adjacency. We present a force-based algorithm that supports these operations. In the design of the algorithm we prioritize the dynamic stability of the map, the accuracy in the size of countries and low complexity of the polygons representing the countries. We evaluate the algorithm based on the state-of-theart quality metrics for randomly generated inputs of various complexity.