Browsing by Subject "Graph Drawing"

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    A circular layout algorithm for clustered graphs
    (2009) Belviranlı, Mehmet Esat
    Visualization of information is essential for comprehension and analysis of the acquired data in any field of study. Graph layout is an important problem in information visualization and plays a crucial role in the drawing of graph-based data. There are many styles and ways to draw a graph depending on the type of the data. Clustered graph visualization is one popular aspect of the graph layout problem and there have been many studies on it. However, only a few of them focus on using circular layout to represent clusters. We present a new, elegant algorithm for layout of clustered graphs using a circular style. The algorithm is based on traditional force-directed layout scheme and uses circles to draw each cluster in the graph. In addition it can handle non-uniform node dimensions. It is the first algorithm to properly address layout of the quotient graph while considering inter-cluster relations as well as intra-cluster edge crossings. Experimental results show that the execution time and quality of the produced drawings with respect to commonly accepted layout criteria are quite satisfactory. The algorithm has been successfully implemented as part of Chisio, version 1.1. Chisio is an open source general purpose graph editor developed by i-Vis (information visualization) Research Group of Bilkent University.
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    A layout algorithm for undirected compount graphs
    (2005) Giral, Erhan
    Graph layout is an important problem in information visualization. All datadriven graph-based information visualization systems require some sort of an automatic geometry generation mechanism, as it is generally not directly available from the data being modeled. This is why graph layout problem has been studied extensively. However, for the case of compound graphs, there are still important gaps in this area. We present a new, elegant algorithm for undirected compound graph layout. The algorithm is based on the traditional force-directed layout scheme with extensions to handle nesting, varying node sizes, and possibly other application-specific constraints. Experimental results show that the execution time and quality of the produced drawings with respect to commonly accepted layout criteria are quite satisfactory. The algorithm has also been successfully implemented as part of a pathway integration and analysis toolkit named Patika for drawing complicated biological pathways with compartmental constraints and arbitrary nesting relations to represent molecular complexes and various types of pathway abstractions.
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    Methods and tools for synchronized visualization of evolving networks
    (2018-07) Safarli, Ilkin
    Graph visualization is a powerful tool to convey and analyze relational information in the form of networks such as biological networks, social networks, and computer networks. Abundant research has been conducted on the automatic layout of static graphs and numerous tools have been developed to visualize them. However, in many applications, graphs are not static; they change or evolve over time. To void this gap, we designed two new dynamic graph layout methods, implemented a dynamic graph layout library and developed a web-based application to visualize and contrast dynamic graphs effectively. Cytoscape.js-synched is a library that implements three different dynamic graph layout algorithms, two of which are proposed by us. In the layout of dynamic graphs, the main criteria is to keep the mental map and minimize the total distance among different versions of the same graphs. It is also important to minimize general layout metrics such as node to node overlaps, number of edge crossing, total area, and total edge length. Proposed and implemented algorithms address both of these conflicting criteria to a satisfactory level and result in aesthetically pleasing layouts. EVEN, which is based on Cytoscape.js graph library, is a highly customizable, open source, web-based, and interactive application for visualization of dynamic graphs. It supports visualization and automatic synchronized layout of two or more dynamic graphs. EVEN makes analysis of dynamic graphs more practical by providing synchronized graph exploration features. It also has basic support for constructing and editing dynamic graph.