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100
StraightLine Drawing Algorithms for Hierarchical Graphs and Clustered Graphs
 Algorithmica
, 1999
"... Hierarchical graphs and clustered graphs are useful nonclassical graph models for structured relational information. Hierarchical graphs are graphs with layering structures; clustered graphs are graphs with recursive clustering structures. Both have applications in CASE tools, software visualizatio ..."
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Cited by 70 (12 self)
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Hierarchical graphs and clustered graphs are useful nonclassical graph models for structured relational information. Hierarchical graphs are graphs with layering structures; clustered graphs are graphs with recursive clustering structures. Both have applications in CASE tools, software visualization, and VLSI design. Drawing algorithms for hierarchical graphs have been well investigated. However, the problem of straightline representation has not been solved completely. In this paper, we answer the question: does every planar hierarchical graph admit a planar straightline hierarchical drawing? We present an algorithm that constructs such drawings in linear time. Also, we answer a basic question for clustered graphs, that is, does every planar clustered graph admit a planar straightline drawing with clusters drawn as convex polygons? We provide a method for such drawings based on our algorithm for hierarchical graphs.
Software visualization in software maintenance, reverse engineering, and reengineering: a research survey
, 2003
"... ..."
Representation Design Benchmarks: A DesignTime Aid for VPL Navigable Static Representations
 Journal of Visual Languages and Computing
, 1997
"... A weakness of many interactive visual programming languages (VPLs) is their static representations. Lack of an adequate static representation places a heavy cognitive burden on a VPL s programmers, because they must remember potentially long dynamic sequences of screen displays in order to understan ..."
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Cited by 36 (14 self)
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A weakness of many interactive visual programming languages (VPLs) is their static representations. Lack of an adequate static representation places a heavy cognitive burden on a VPL s programmers, because they must remember potentially long dynamic sequences of screen displays in order to understand a previously written program. However, although this problem is widely acknowledged, research on how to design better static representations for interactive VPLs is still in its infancy. Building upon the cognitive dimensions developed for programming languages by cognitive psychologists Green and others, we have developed a set of concrete benchmarks for VPL designers to use when designing new static representations. These benchmarks provide designtime information that can be used to improve a VPL s static representation.
Explorations into the Visualization of Policy Networks
 JOURNAL OF THEORETICAL POLITICS
, 1998
"... Visualization is an important aspect of both exploration and communication of categorical as well as relational data. Graphical displays of policy networks are particularly attractive, since they enable authors to display in a compact way relevant actors in a network, how they are related to each ot ..."
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Cited by 28 (18 self)
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Visualization is an important aspect of both exploration and communication of categorical as well as relational data. Graphical displays of policy networks are particularly attractive, since they enable authors to display in a compact way relevant actors in a network, how they are related to each other, and what the overall structure looks like. Sociograms were early companions of social network analysis, but have received surprisingly little attention during the following decades. Only in the last few years, easy accessability of quality computing and graphic equipment has revived a now rapidly growing interest. In this paper, we analyze the problem of visualizing policy networks. We first argue why network visualization is important, yet nontrivial. Then, we show that current methods are somewhat ad hoc in their attempt to convey information contained in a network. Our main contribution is a systematic approach to network visualization, closely following the general principles of in...
Using Genetic Algorithms for Drawing Undirected Graphs
 The Third Nordic Workshop on Genetic Algorithms and their Applications
, 1996
"... In this paper we report on our experiences with applying genetic algorithms to the drawing of undirected graphs with straight line edges. Since there exists a relatively simple but powerful heuristic for this class of graphs, namely the spring algorithm, we use this algorithm as a local finetuner w ..."
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Cited by 26 (1 self)
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In this paper we report on our experiences with applying genetic algorithms to the drawing of undirected graphs with straight line edges. Since there exists a relatively simple but powerful heuristic for this class of graphs, namely the spring algorithm, we use this algorithm as a local finetuner within the genetic algorithm. We compare our results with drawings produced by the spring algorithm alone and discuss the strengths and weaknesses of the approach presented. Keywords: spring algorithm, evolutionary algorithm, genetic algorithm, graph drawing 1 Introduction The problem of drawing a graph nicely can be regarded as searching for an optimal layout of a given graph according to some measurable aesthetics. However, solving this problem to optimality seems to be computationally infeasible even for relatively simple aesthetic criteria [7], thus one is bound to the area of heuristics and stochastic search methods. In recent years, a lot of research on the problem to support the auto...
Graphs, they are changing  dynamic graph drawing for a sequence of graphs
 Proc. 10th Int. Symp. Graph Drawing (GD 2002), number 2528 in Lecture Notes in Computer Science, LNCS
, 2002
"... Abstract. In this paper we present a generic algorithm for drawing sequences of graphs. This algorithm works for different layout algorithms and related metrics and adjustment strategies. It differs from previous work on dynamic graph drawing in that it considers all graphs in the sequence (offline) ..."
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Cited by 23 (1 self)
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Abstract. In this paper we present a generic algorithm for drawing sequences of graphs. This algorithm works for different layout algorithms and related metrics and adjustment strategies. It differs from previous work on dynamic graph drawing in that it considers all graphs in the sequence (offline) instead of just the previous ones (online) when computing the layout for each graph of the sequence. We introduce several general adjustment strategies and give examples of these strategies in the context of forcedirected graph layout. Finally some results from our first prototype implementation are discussed. 1
Visualization of Graphs with Associated Timeseries Data
"... The most common approach to support analysis of graphs with associated time series data include: overlay of data on graph vertices for one timepoint at a time by manipulating a visual property (e.g. color) of the vertex, along with sliders or some such mechanism to animate the graph for other timepo ..."
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Cited by 22 (3 self)
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The most common approach to support analysis of graphs with associated time series data include: overlay of data on graph vertices for one timepoint at a time by manipulating a visual property (e.g. color) of the vertex, along with sliders or some such mechanism to animate the graph for other timepoints. Alternatively, data from all the timepoints can be overlaid simultaneously by embedding small charts into graph vertices. These graph visualizations may also be linked to other visualizations (e.g., parallel coordinates) using brushing and linking. This paper describes a study performed to evaluate and rank graph+timeseries visualization options based on users’ performance time and accuracy of responses on predefined tasks. The results suggest that overlaying data on graph vertices one timepoint at a time may lead to more accurate performance for tasks involving analysis of a graph at a single timepoint, and comparisons between graph vertices for two distinct timepoints. Overlaying data simultaneously for all the timepoints on graph vertices may lead to more accurate and faster performance for tasks involving searching for outlier vertices displaying different behavior than the rest of the graph vertices for all timepoints. Single views have advantage over multiple views on tasks that require topological information. Also, the number of attributes displayed on nodes has a non trivial influence on accuracy of responses, whereas the number of visualizations affect the performance time.
Integrating edge routing into forcedirected layout
 IN: PROC. 14TH INTL. SYMP. GRAPH DRAWING (GD ’06). VOLUME 4372 OF LECTURE
, 2007
"... Forcedirected layout is typically used to create organiclooking, straightedge drawings of large graphs while combinatorial techniques are generally preferred for highquality layout of small to medium sized graphs. In this paper we integrate edgerouting techniques into a forcedirected layout me ..."
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Cited by 18 (4 self)
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Forcedirected layout is typically used to create organiclooking, straightedge drawings of large graphs while combinatorial techniques are generally preferred for highquality layout of small to medium sized graphs. In this paper we integrate edgerouting techniques into a forcedirected layout method based on constrained stress majorisation. Our basic procedure takes an initial layout for the graph, including polyline paths for the edges, and improves this layout by moving the nodes to reduce stress and moving edge bend points to straighten the edges and reduce their overall length. Separation constraints between nodes and edge bend points are used to ensure that node labels do not overlap edges or other nodes and that no additional edge crossings are introduced.
Improving graph drawing readability by incorporating readability metrics: A software tool for network analysts
, 2009
"... Designing graph drawings that effectively communicate the underlying network is challenging as for every network there are many potential unintelligible or even misleading drawings. Automated graph layout algorithms have helped, but frequently generate ineffective drawings. In order to build awarene ..."
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Cited by 17 (9 self)
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Designing graph drawings that effectively communicate the underlying network is challenging as for every network there are many potential unintelligible or even misleading drawings. Automated graph layout algorithms have helped, but frequently generate ineffective drawings. In order to build awareness of effective graph drawing strategies, we detail readability metrics on a [0,1] continuous scale for node occlusion, edge crossing, edge crossing angle, and edge tunneling and summarize many more. Additionally, we define new node & edge readability metrics to provide more localized identification of where improvement is needed. These are implemented in SocialAction, a tool for social network analysis, in order to direct users towards poor areas of the drawing and provide realtime readability metric feedback as users manipulate it. These contributions are aimed at heightening the awareness of network analysts that the images they share or publish could be of higher quality, so that readers could extract relevant information.