Abstract Visualizing 3D vector fields is challenging because of occlusion problems and the difficulty of providing depth cues that adequately support the perception of direction of flow lines in 3D space. One of the depth cues that has proven most valuable for the perception of other kinds of 3D data, notably 3D networks and 3D point clouds, is structure‐from‐motion (also called the Kinetic Depth Effect); another powerful depth cue is stereoscopic viewing. We carried out an experiment of the perception of direction for short streamlines passing through a cutting plane. The conditions included viewing with and without structure‐from‐motion and with and without stereoscopic depth. Conditions also include comparing streamtubes to lines. The results show that for this particular task, stereo provided an effective depth cue, but structure‐from‐motion did not. Ringed streamtubes and streamcones provided good 3D direction information, even without stereoscopic viewing. We conclude with guidelines for viewing slices through vector fields.

One advantage of touch interaction is the sense of direct manipulation; there is perhaps no more-intuitive interface than just reaching out and touching virtual entities. However, direct manipulation is generally limited to objects located on the 2D display surface. For 3D spaces extending behind or in front of a touchscreen, the direct manipulation metaphor quickly falls apart. In these cases, gestures are needed to convert 2D finger positions into 3D cursor positions. This paper presents the pantograph technique, a simple two-finger interaction method for positioning a 3D cursor within mono and stereoscopic applications. The pantograph's pseudomechanical linkage between fingers and cursor provides helpful depth cues and maintains the sense of direct manipulation. Extensions to the technique, which integrate selection and other advanced actions, are explored within the context of real-world visual analysis applications. A series of human factors experiments showed that, while the pantograph technique outperformed other similar multitouch 3D positioning techniques, multi-touch was still inferior to other traditional, non-touch-based interfaces for sustained 3D positioning tasks.

We developed a virtual reality interface for cleaning sonar point cloud data. Experimentally, users performed better when using this VR interface compared to a mouse-and-keyboard with a desktop monitor. However, hydrographers often clean data aboard moving vessels, which can create motion sickness. Users of VR experience motion sickness as well, in the form of simulator sickness. Combining the two is a worst-case scenario for motion sickness. Advice for avoiding seasickness includes focusing on the horizon or objects in the distance, to keep your frame of reference external. We explored moving the surroundings in a virtual environment to match vessel motion, to assess whether it provides similar visual cues that could prevent seasickness. An informal evaluation in a seasickness-inducing simulator was conducted, and subjective preliminary results hint at such compensation's potential for reducing motion sickness, enabling the use of immersive VR technologies aboard underway ships.

Three-dimensional vector fields are common datasets throughout the sciences. Visualizing these fields is inherently difficult due to issues such as visual clutter and self-occlusion. Cutting planes are often used to overcome these issues by presenting more manageable slices of data. The existing literature provides many techniques for visualizing the flow through these cutting planes; however, there is a lack of empirical studies focused on the underlying perceptual cues that make popular techniques successful. This paper presents a quantitative human factors study that evaluates static monoscopic depth and orientation cues in the context of cutting plane glyph designs for exploring and analyzing 3D flow fields. The goal of the study was to ascertain the relative effectiveness of various techniques for portraying the direction of flow through a cutting plane at a given point, and to identify the visual cues and combinations of cues involved, and how they contribute to accurate performance. It was found that increasing the dimensionality of line-based glyphs into tubular structures enhances their ability to convey orientation through shading, and that increasing their diameter intensifies this effect. These tube-based glyphs were also less sensitive to visual clutter issues at higher densities. Adding shadows to lines was also found to increase perception of flow direction. Implications of the experimental results are discussed and extrapolated into a number of guidelines for designing more perceptually effective glyphs for 3D vector field visualizations.

Previous perceptual research and human factors studies have identified several effective methods for texturing 3D surfaces to ensure that their curvature is accurately perceived by viewers. However, most of these studies examined the application of these techniques to static surfaces. This paper explores the effectiveness of applying these techniques to dynamically changing surfaces. When these surfaces change shape, common texturing methods, such as grids and contours, induce a range of different motion cues, which can draw attention and provide information about the size, shape, and rate of change. A human factors study was conducted to evaluate the relative effectiveness of these methods when applied to dynamically changing pseudo-terrain surfaces. The results indicate that, while no technique is most effective for all cases, contour lines generally perform best, and that the pseudocontour lines induced by banded color scales convey the same benefits.

We present research focused on designing visual analytics (VA) systems for workers in organizational environments. We focus on business analysts and asset managers, who work collaboratively to analyze information and make decisions. Through extensive investigations in two organizational environments, we found that these users struggle with managing and analyzing information from multiple perspectives. Their current tools lack support for aggregating, organizing, and sharing such information. To address their needs, we characterized their analytic workflows, extracted specific key knowledge actions for each task commonly found in these workflows, and designed and evaluated two visual analytics systems that support and encapsulate these knowledge actions. We provide design guidelines that should be used when designing visual analytics systems, and illustrate their effectiveness with two systems built by following them.

Abstract We present a probe‐based interface for the exploration of the results of a geospatial simulation of urban growth. Because our interface allows the user great freedom in how they choose to define regions‐of‐interest to examine and compare, the classic geospatial analytic issue known as the modifiable areal unit problem (MAUP) quickly arises. The user may delineate regions with unseen differences that can affect the fairness of the comparisons made between them. To alleviate this problem, our interface first alerts the user if it detects any potential unfairness between regions when they are selected for comparison. It then presents the dimensions with potential problematic outliers to the user for evaluation. Finally, it provides a number of semi‐automated tools to assist the user in correcting their regions' boundaries to minimize the inequalities they feel could significantly impact their comparisons.

Abstract Many previous approaches to detecting urban change from LIDAR point clouds interpolate the points into rasters, perform pixel‐based image processing to detect changes, and produce 2D images as output. We present a method of LIDAR change detection that maintains accuracy by only using the raw, irregularly spaced LIDAR points, and extracts relevant changes as individual 3D models. We then utilize these models, alongside existing GIS data, within an interactive application that allows the chronological exploration of the changes to an urban environment. A three‐tiered level‐of‐detail system maintains a scale‐appropriate, legible visual representation across the entire range of view scales, from individual changes such as buildings and trees, to groups of changes such as new residential developments, deforestation, and construction sites, and finally to larger regions such as neighborhoods and districts of a city that are emerging or undergoing revitalization. Tools are provided to assist the visual analysis by urban planners and historians through semantic categorization and filtering of the changes presented.

Traditional geospatial information visualizations often present views that restrict the user to a single perspective. When zoomed out, local trends and anomalies become suppressed and lost; when zoomed in for local inspection, spatial awareness and comparison between regions become limited. In our model, coordinated visualizations are integrated within individual probe interfaces, which depict the local data in user-defined regions-of-interest. Our probe concept can be incorporated into a variety of geospatial visualizations to empower users with the ability to observe, coordinate, and compare data across multiple local regions. It is especially useful when dealing with complex simulations or analyses where behavior in various localities differs from other localities and from the system as a whole. We illustrate the effectiveness of our technique over traditional interfaces by incorporating it within three existing geospatial visualization systems: an agent-based social simulation, a census data exploration tool, and an 3D GIS environment for analyzing urban change over time. In each case, the probe-based interaction enhances spatial awareness, improves inspection and comparison capabilities, expands the range of scopes, and facilitates collaboration among multiple users.

In this paper, we describe our current work in developing a computer-based educational tool for Occupational Therapy students learning client evaluation techniques. The software is dialog-based and allows the student to interact with a virtual client. Students carry out an evaluation, following the appropriate procedures and assessing both the client's physical and emotional state as they proceed. Students' actions are saved to a file for instructor and self evaluation of their performance. The software is being developed using the Source® game engine SDK developed by Valve™.