Information Visualization Applications Research Articles

Color Lens: Adaptive Color Scale Optimization for Visual Exploration

Visualization applications routinely map quantitative attributes to color using color scales. Although color is an effective visualization channel, it is limited by both display hardware and the human visual system. We propose a new interaction technique that overcomes these limitations by dynamically optimizing color scales based on a set of sampling lenses. The technique inspects the lens contents in data space, optimizes the initial color scale, and then renders the contents of the lens to the screen using the modified color scale. We present two prototype implementations of this pipeline and describe several case studies involving both information visualization and image inspection applications. We validate our approach with two mutually linked and complementary user studies comparing the Color Lens with explicit contrast control for visual search.

DaisyViz: A model-based user interface toolkit for interactive information visualization systems

While information visualization technologies have transformed our life and work, designing information visualization systems still faces challenges. Non-expert users or end-users need toolkits that allow for rapid design and prototyping, along with supporting unified data structures suitable for different data types (e.g., tree, network, temporal, and multi-dimensional data), various visualization, interaction tasks. To address these issues, we designed DaisyViz, a model-based user interface toolkit, which enables end-users to rapidly develop domain-specific information visualization applications without traditional programming. DaisyViz is based on a user interface model for information (UIMI), which includes three declarative models: data model, visualization model, and control model. In the development process, a user first constructs a UIMI with interactive visual tools. The results of the UIMI are then parsed to generate a prototype system automatically. In this paper, we discuss the concept of UIMI, describe the architecture of DaisyViz, and show how to use DaisyViz to build an information visualization system. We also present a usability study of DaisyViz we conducted. Our findings indicate DaisyViz is an effective toolkit to help end-users build interactive information visualization systems.

Systems biology visualization tools for drug target discovery

Importance of the field: Post-genome drug development has been driven by the need to study biological perturbations at the molecular system level. Systems biology visualization tools can help researchers extract hidden patterns from complex and large Omics data sets, model disease molecular mechanisms, and identify drug targets and drugs with good pharmacological and toxicological profiles.Areas covered in this review: This review covers basic concepts in developing and applying information visualization tools to systems biology. We describe a framework and basic data representation schemes for visual data analysis in systems biology. We review major application areas of these visualization tools within drug discovery by focusing on early-stage drug discovery tasks such as disease biology modeling, target identifications and lead identification. We also show case studies and summarize our experience using visualization tools as lessons to our readers.What the reader will gain: The reader will understand what visualization tools are available for diverse types of systems biology studies in drug discovery and understand how these tools can help advance drug development.Take home message: In spite of the complexity inherent in systems biology, proper use of information visualization tools may reveal emerging properties hidden in the data and enhance chances of success for drug discovery.

A Network-Based Radiometric Equalization Approach for Digital Aerial Orthoimages

Digital aerial orthoimages have been widely used in surveying, mapping, geographic information systems, visualization, and other applications. However, when producing digital aerial orthoimages, radiometric equalization over large areas is often a most time-consuming and costly process and has become a bottleneck. This letter presents a network-based radiometric equalization approach to eliminate the radiometric differences between images. The network is constructed using the area Voronoi diagrams with overlap and is based on the topological relationship of the constructed network; transferring paths between images are determined, and a global-to-local strategy is used to improve the algorithm, both in its global and local performance. Digital aerial orthoimages from both film-based and digital cameras are used to evaluate the performance of the presented algorithm.

The Benefits of Synchronous Collaborative Information Visualization: Evidence from an Experimental Evaluation

A great corpus of studies reports empirical evidence of how information visualization supports comprehension and analysis of data. The benefits of visualization for synchronous group knowledge work, however, have not been addressed extensively. Anecdotal evidence and use cases illustrate the benefits of synchronous collaborative information visualization, but very few empirical studies have rigorously examined the impact of visualization on group knowledge work. We have consequently designed and conducted an experiment in which we have analyzed the impact of visualization on knowledge sharing in situated work groups. Our experimental study consists of evaluating the performance of 131 subjects (all experienced managers) in groups of 5 (for a total of 26 groups), working together on a real-life knowledge sharing task. We compare (1) the control condition (no visualization provided), with two visualization supports: (2) optimal and (3) suboptimal visualization (based on a previous survey). The facilitator of each group was asked to populate the provided interactive visual template with insights from the group, and to organize the contributions according to the group consensus. We have evaluated the results through both objective and subjective measures. Our statistical analysis clearly shows that interactive visualization has a statistically significant, objective and positive impact on the outcomes of knowledge sharing, but that the subjects seem not to be aware of this. In particular, groups supported by visualization achieved higher productivity, higher quality of outcome and greater knowledge gains. No statistically significant results could be found between an optimal and a suboptimal visualization though (as classified by the pre-experiment survey). Subjects also did not seem to be aware of the benefits that the visualizations provided as no difference between the visualization and the control conditions was found for the self-reported measures of satisfaction and participation. An implication of our study for information visualization applications is to extend them by using real-time group annotation functionalities that aid in the group sense making process of the represented data.

A Novel Visualization Technique for Electric Power Grid Analytics

The application of information visualization holds tremendous promise for the electric power industry, but its potential has so far not been sufficiently exploited by the visualization community. Prior work on visualizing electric power systems has been limited to depicting raw or processed information on top of a geographic layout. Little effort has been devoted to visualizing the physics of the power grids, which ultimately determines the condition and stability of the electricity infrastructure. Based on this assessment, we developed a novel visualization system prototype, GreenGrid, to explore the planning and monitoring of the North American Electricity Infrastructure. The paper discusses the rationale underlying the GreenGrid design, describes its implementation and performance details, and assesses its strengths and weaknesses against the current geographic-based power grid visualization. We also present a case study using GreenGrid to analyze the information collected moments before the last major electric blackout in the Western United States and Canada, and a usability study to evaluate the practical significance of our design in simulated real-life situations. Our result indicates that many of the disturbance characteristics can be readily identified with the proper form of visualization.

PRISAD: A Partitioned Rendering Infrastructure for Scalable Accordion Drawing (Extended Version)

We present PRISAD, the first generic rendering infrastructure for information visualization applications that use the accordion drawing technique: rubber-sheet navigation with guaranteed visibility for marked areas of interest. Our new rendering algorithms are based on the partitioning of screen-space, which allows us to handle dense data set regions correctly. The algorithms in previous work led to incorrect visual representations because of overculling, and to inefficiencies due to overdrawing multiple items in the same region. Our pixel-based drawing infrastructure guarantees correctness by eliminating over-culling, and improves rendering performance with tight bounds on overdrawing. PRITree and PRISeq are applications built on PRISAD, with the feature sets of TreeJuxtaposer and SequenceJuxtaposer, respectively. We describe our PRITree and PRISeq data set traversal algorithms, which are used for efficient rendering, culling, and layout of data sets within the PRISAD framework. We also discuss PRITree node marking techniques, which offer order-of-magnitude improvements to both memory and time performance vs previous range storage and retrieval techniques. Our PRITree implementation features a fivefold increase in rendering speed for non-trivial tree structures, and also reduces memory requirements in some real-world data sets by up to eight times, so we are able to handle trees of several million nodes. PRISeq renders 15 times faster and handles data sets 20 times larger than previous work. The software is available as open source from http://olduvai.sourceforge.net .

PRISAD: a partitioned rendering infrastructure for scalable accordion drawing (extended version)

We present PRISAD, the first generic rendering infrastructure for information visualization applications that use the accordion drawing technique: rubber-sheet navigation with guaranteed visibility for marked areas of interest. Our new rendering algorithms are based on the partitioning of screen-space, which allows us to handle dense data set regions correctly. The algorithms in previous work led to incorrect visual representations because of overculling, and to inefficiencies due to overdrawing multiple items in the same region. Our pixel-based drawing infrastructure guarantees correctness by eliminating overculling, and improves rendering performance with tight bounds on overdrawing. PRITree and PRISeq are applications built on PRISAD, with the feature sets of TreeJuxtaposer and SequenceJuxtaposer, respectively. We describe our PRITree and PRISeq data set traversal algorithms, which are used for efficient rendering, culling, and layout of data sets within the PRISAD framework. We also discuss PRITree node marking techniques, which offer order-of-magnitude improvements to both memory and time performance vs previous range storage and retrieval techniques. Our PRITree implementation features a fivefold increase in rendering speed for non-trivial tree structures, and also reduces memory requirements in some real-world data sets by up to eight times, so we are able to handle trees of several million nodes. PRISeq renders 15 times faster and handles data sets 20 times larger than previous work. The software is available as open source from http://olduvai.sourceforge.net.

Overview + Detail in a Tomahawk Mission-to-Platform Assignment Tool: Applying Information Visualization in Support of an Asset Allocation Planning Task

Information visualization techniques such as overview + detail displays have traditionally been applied and studied in domains with static data sets supporting information retrieval tasks. This study examines how these techniques can be extended to the design of interfaces for decision support systems (DSSs). Specifically, we developed a computerized decision support tool to assist Naval Tomahawk Strike Coordinators in the complex process of assigning a set of planned missions to a set of available launch platforms based on a number of different constraints and objectives, and compared user performance on two realistic scenarios (a within-subjects factor) across two versions of this tool (a between-subjects factor). The first version of the Mission-to-Platform Assignment Tool provided users with only a set of detail displays when assigning missions, whereas the second version had an additional, abstracted ‘overview’ display that allowed users to see the effect of early decisions on later decisions. The results showed that subjects performing this planning task with the overview + details display version completed scenarios, on average, 21% faster, with 22% fewer errors and with 74% fewer required workspace navigation activities than a comparable group using just the detail displays version. Subjects in the former group also rated their situational awareness 14% higher than those subjects without the overview display.

Guest Editor's Introduction: Special Issue on Selected InfoVis 2002 Papers

It is an honor to welcome you to the first theme issue of Information Visualization dedicated entirely to the papers selected from IEEE Symposium on Information Visualization (InfoVis) 2002. The annual InfoVis symposium, which has been held in conjunction with the annual IEEE Visualization Conference since 1995, is the leading technical forum to showcase the research and applications in information visualization. This year paper acceptance fell to only 27%, indicating that the InfoVis 2002 program represents the highest quality and most up to date work contributed by researchers and practitioners of the community. The intent of this special issue is to bring this exciting work to our broad journal readership as an overview for future research and a foundation for further development.

Multivariate Visualization with Data Fusion

We discuss a fusion-based visualization method to analyze a multivariate climate dataset and its metadata. The primary difference between a conventional visualization and a fusion-based visualization is that the former draws on a single image whereas the latter draws on multiple see-through layers, which are then overlaid on each other to form the final visualization. We propose optimized colormaps to highlight subtle features that would not be shown with conventional colormaps. We present fusion techniques that integrate multiple single-purpose visualization techniques into the same viewing space. Our highly flexible fusion approach allows scientists to explore multiple parameters concurrently by mixing and matching images without frequently reconstructing new visualizations from the data for every possible combination. Although our primary visualization application is climate modeling, we show with examples that our fundamental design - fusing layers of data images for multivariate visualization - can be generalized for other information visualization applications.

Towards area requirements for drawing hierarchically planar graphs

Hierarchical graphs are an important class of graphs for modeling many real applications in software and information visualization. In this paper, we investigate area requirements for drawing hierarchically planar graphs regarding two different drawing standards. Firstly, we show an exponential lower bound for the area needed for straight-line drawing of hierarchically planar graphs. The lower bound holds even for s- t hierarchical graphs without transitive arcs, in contrast to the results for upward planar drawing. This motivates our investigation of another drawing standard grid visibility representation, as a relaxation of straight-line drawing. An application of the existing results from upward drawing can guarantee a quadric drawing area for grid visibility representation but does not necessarily guarantee the minimum drawing area. Motivated by this, we will present a new grid visibility drawing algorithm which is efficient and guarantees the minimum drawing area with respect to a given topological embedding. This implies that the area minimization problem is polynomial time solvable restricted to the class of graphs whose planar embeddings are unique. However, we can show that the problem of area minimization of grid visibility for hierarchically planar graphs is generally NP-hard, even restricted to s- t graphs.

Focus+context taken literally

A common feature of information visualization applications, and also other areas, is to direct the user's attention to certain objects. This alerts users to a problem or shows the matching objects in response to a query. Often users also want to quickly understand the information pointed out in the context of the other information and not just see the results. This is one type of the focus+context (F+C) technique, which provides both detailed information of the currently most relevant objects, as well as giving users an idea of the context. The authors present a focus+context method that blurs objects based on their relevance (rather than distance) to direct the user's attention.

A virtual GIS-based hydrodynamic model system for Tamshui River

A computer infrastructure which integrates the geographic information system (GIS), hydrodynamic model, visualization and network applications was developed and applied in Tamshui River, Taiwan. A digital terrain model (DTM) of the study area was first generated. We used it as a basis to construct the computation grids, conduct the flow simulations, and visualize the predicted flow scenarios in the virtual world. The three-dimensional hydrodynamic and water quality model system WQMAP was employed to simulate flows under the tidal forcing, upstream river inflows and seawater–freshwater interactions of Tamshui River. Model predictions were generally in good agreement with other simulations. Computed results were visualized in both the innovative virtual reality (VR) environment and Internet-based collaborative visualization environment (CVE). The VR environment enabled us to observe firsthand the complicated flow phenomena in the virtual world. Internet-based CVE supports distributed visualization and collaboration. The GIS-based system exhibits great potential in data visualization capabilities and the improvement of water management. We anticipate that these computer technologies will popularly be applied to hydroinformatics and other related domains in the foreseeable future.

Information visualization for intelligent decision support systems

To work efficiently with decision support systems (DSS), most users benefit from representation conversion, i.e. translating the specific outcome from the DSS, normally portrayed in a numerical format, into the universal language of the visual. In general, interpretation of data is much more intuitive if the results from the DSS are translated into charts, maps, and other graphical displays because visualization exploits our natural ability to recognize and understand visual patterns. In this paper we discuss the concept of visualization user interface (VUI) for DSS. A proprietary software system known as AniGraftool is introduced as an example of an information visualization application for DSS. In addition, a visualized information retrieval engine based on fuzzy control is proposed.

Navigating Clustered Graphs Using Force-Directed Methods

Graphs which arise in Information Visualization applications are typically very large: thousands, or perhaps millions of nodes. Current graph drawing methods successfully deal with (at best) a few hundred nodes. This paper describes a strategy for the visualization and navigation of graphs. The strategy has three elements:

Web-based information visualization

Increasingly, the World Wide Web is being used to help visualize complex relational information. We have developed a number of Web-based information visualization prototypes and applications by adapting several well-known information visualization ideas and techniques for use within Web environments. Before delving into specific examples, we offer some relevant background about the Web and our use of visualization for analysis.

Business visualization applications

Three-dimensional computer graphics can be extremely expressive. With the correct approach to a layout's visual design, people can quickly and easily comprehend large amounts of information. You can convey far more information in 3D than with 2D bar charts, or rows and columns of numbers. This article provides examples of information visualization applications in several industries, including the capital markets, retail banking, manufacturing, and consumer product goods. These examples help show what it means to put abstract information in 3D and what benefits result.