The dataflow model : a characterization and a data exploration tool

Doctoral ColloquiumInternational audienceCurrent Air Traffic Control (ATC) activities employ two kinds of visualization systems: real-time traffic views, which are used by Air Traffic Controllers (ATCos) to monitor aircraft positions, and data analysis systems, used by experts to analyze past traffic recording (e.g. conflict analysis or traffic workload forecast). Both types of systems employ complex and dynamic visualizations, displaying hundreds of data that must be understandable with the minimum of cognitive workload

Techniques de bundling : un cas d'étude pour l'exploration de grandes quantités d'informations

We present a fast and simple method to compute bundled layouts of general graphs, dynamic graphs and temporal paths. For this, we first transform a given graph drawing into a density map using kernel density estimation. Next, we apply an image sharpening technique which progressively merges local height maxima by moving the convolved graph edges into the height gradient flow. We show how these techniques can produce simplified visualizations of static, streaming and sequence graphs. We illustrate our techniques with datasets from aircraft monitoring, software engineering, and eye-tracking of static and dynamic scenes

Exploration of aircraft trails by Air Traffic Experts

International audienceIn this paper, we describe a set of applications and findings performed by Air Traffic Control (ATC) experts while interactively exploring recorded aircraft trails. ATC experts deal with recorded radar data (aircraft positions, altitude, time, etc). This large quantity of information spoils their visualization with a lot of occlusion and cluttering. With a simple paradigm of brush, pick and drop, users can intuitively filter the dataset by direct manipulation of trails. Through applied examples, we show how a visualization tool and its real time applications take advantage of human vision and are therefore assets for data exploration and validation. This tool allows the visualization and the interaction with large quantity of information, hence enabling overview of the dataset at a whole and quick retrieval of insights

The Physiological User's Response as a Clue to Assess Visual Variables Effectiveness

International audienceThe paper deals with the introduction of Bertin's visual variables in an ATC context. The ranking of the efficiency of these variables has been experimentally verified by Cleveland, however, no studies highlight the physiological correlates of this ranking. We analyzed behavioral, physiological and subjective data recorded on 7 healthy subjects facing a visual comparison task witch involve 5 selected visual characterizations (angle, text, surface, framed rectangles and luminosity). Results showed that the observed accuracy was coherent with Mackinlay ranking of visual variables. Psychophysiological and subjective measurements are also discussed

Scan path visualization and comparison using visual aggregation techniques

We demonstrate the use of different visual aggregation techniques to obtain non-cluttered visual representations of scanpaths. First, fixation points are clustered using the mean-shift algorithm. Second, saccades are aggregated using the Attribute-Driven Edge Bundling (ADEB) algorithm that handles a saccades direction, onset timestamp, magnitude or their combination for the edge compatibility criterion. Flow direction maps, computed during bundling, can be visualized separately (vertical or horizontal components) or as a single image using the Oriented Line Integral Convolution (OLIC) algorithm. Furthermore, cosine similarity between two flow direction maps provides a similarity map to compare two scanpaths. Last, we provide examples of basic patterns, visual search task, and art perception. Used together, these techniques provide valuable insights about scanpath exploration and informative illustrations of the eye movement data

Extension d'un modèle de visualisation pour la caracterisation d'interfaces graphiques dynamiques

International audienceLes systèmes de contrôle du trafic aérien présentent des informations en utilisant de multiples variables visuelles. Dans cet article, nous caractérisons quatre de ces systèmes en utilisant le modèle de Card, Mackinlay et Bertin. La spécificité des visualisations étudiées nous amène à étendre ce modèle en différenciant les formes codant l'information volontairement, des formes générées par le processus d'émergence de la Gestalt , en précisant les relations hiérarchiques entre éléments graphiques, et en explicitant le rôle du temps dans la dynamique de l'interface. Ces travaux permettent de caractériser plus précisément les visualisations, d'affiner notre compréhension des transformations qui génèrent une visualisation, ainsi que le rôle de la perception dans l'interprétation d'une visualisation.The air traffic control systems display information using multiple visual variables. In this article, we characterize these systems using Card, Mackinlay and Bertin model. The specificity of the visualizations we studied leads us to extend this model by clarifying the role of time in the dynamics of the interface, and by differentiating the forms coding information deliberately, from the forms generated by the emergence process of the Gestalt. This work helps characterize visualizations more precisely, refine our understanding of the transformations that generate visualization, as well as the role of perception in the interpretation of a visualization

Amélioration du circuit visuel des contrôleurs aériens pour relier les données entre visualisations en utilisant des transitions animées

International audienceSeveral separate displays are used by Air Traffic Controllers, such as radar view, flight lists view or paper strips. In order to link the information between these views and keep focus on a subset of flights, controllers are required to do visual operations (eye gaze, analysis of visual properties etc.). This process can be disruptive when traffic increases and when visualizations display large amounts of objects. In this paper we propose the use of animated transitions to replace the visual paths controllers take. We discuss this technique and show results of a predictive evaluation that suggests an improvement in users' performance

Experimenting and improving perception of 3D rotation-based transitions between 2D visualizations

Part 1: Long and Short PapersInternational audienceExploring a multidimensional dataset with visualization requires to transition between points of view. In order to enable users to understand transitions, visualization can employ progressive 3D rotations. However, existing implementations of progressive 3D rotation exhibit some perception problems with visualization of cluttered scene. In this paper, we present a first experiment showing how existing 3D rotation is effective for tracking marks, and that cluttered scenes actually hinder perception of rotation. Then, we propose to set the axis of rotation on the graphical marks of interest, and ran a second experiment showing that focus-centered rotation improves perception of relative arrangement

Uncertainty visualization of gaze estimation to support operator-controlled calibration

      In this paper, we investigate how visualization assets can support the qualitative evaluation of gaze estimation uncertainty. Although eye tracking data are commonly available, little has been done to visually investigate the uncertainty of recorded gaze information. This paper tries to fill this gap by using innovative uncertainty computation and visualization. Given a gaze processing pipeline, we estimate the location of this gaze position in the world camera. To do so we developed our own gaze data processing which give us access to every stage of the data transformation and thus the uncertainty computation. To validate our gaze estimation pipeline, we designed an experiment with 12 participants and showed that the correction methods we proposed reduced the Mean Angular Error by about 1.32 cm, aggregating all 12 participants’ results. The Mean Angular Error is 0.25° (SD=0.15°) after correction of the estimated gaze. Next, to support the qualitative assessment of this data, we provide a map which codes the actual uncertainty in the user point of view.

Accumulation as a tool for efficient visualization of geographical and temporal data

International audienceIn this paper, we describe a set of visualization methods with an accumulation tool to perform interactive data exploration. Accumulation maps or Kernel Density Estimation (KDE) maps, count the amount of data accumulated at a certain location. The accumulation tool addresses the cluttering issues when displaying large amounts of data. But the accumulation tool can also be used to unveil patterns, to detect outliers and flaws in datasets. Through these applied examples, we show how the accumulation tool and its real time applications take advantage of human vision and are therefore assets for data exploration and validation. As the accumulation tool uses GPU techniques, it can be used in real-time with large datasets