The emergence of very large hierarchies that result from the increase in available data raises many problems of visualization and navigation. On data sets of such scale, classical graph drawing methods do not take advantage of certain human cognitive skills such as shape recognition. These cognitive skills could make it easier to remember the global structure of the data. In this paper, we propose a method that is based on the use of nested irregular shapes. We name it GosperMap as we rely on the use of a Gosper Curve to generate these shapes. By employing human perception mechanisms that were developed by handling, for example, cartographic maps, this technique facilitates the visualization and navigation of a hierarchy. An algorithm has been designed to preserve region containment according to the hierarchy and to set the leaves' sizes proportionally to a property, in such a way that the size of nonleaf regions corresponds to the sum of their children's sizes. Moreover, the input ordering of the hierarchy's nodes is preserved, i.e., the areas that represent two consecutive children of a node in the hierarchy are adjacent to one another. This property is especially useful because it guarantees some stability in our algorithm. We illustrate our technique by providing visualization examples of the repartition of tax money in the US over time. Furthermore, we validate the use of the GosperMap in a professional documentation context and show the stability and ease of memorization for this type of map.

With the increase of online resources, one main challenge for multimedia content providers is to provide efficient and user friendly tools for a deep and shallow navigation adapted to large scale audiovisual content. This paper describes a generic framework to build visual interactive applications the objectives of which are to enhance the understanding and to allow easy access to multimedia resources and management. Visual Maps are built on multi-modal similarity matrices computed from automatically extracted descriptors and use graph clustering and layout methods. Active relevance feedback methods are applied to allow users to control the maps evolution according to their needs. The First results of users' evaluation are presented for one of our tools.

RESUMELa sémiologie graphique telle qu'elle a été introduite par Bertin définit un système de signes complet, indépendant et possédant ses lois propres pour construire des images sur un plan. C'est un système très puissant pour retenir comprendre et communiquer des informations. Dans cet article, nous nous appuyons sur des résultats d'expériences menées sur la perception du mouvement pour émettre des hypothèses sur l'extension de la sémiologie graphique aux systèmes de visualisation graphique interactifs. Pour cela, aux variables visuelles de Bertin que sont l'ensemble des variables rétiniennes et les deux dimensions du plan, nous tenterons d'introduire le temps en proposant d'ajouter la variable mouvement. ABSTRACTThe semiology of graphics introduced by Bertin is a complete system composed of signs and rules in order to build planar maps or diagrams. This system is powerfull to represent, memorize, understand and communicate information. In this paper, we study experiments in motion perception to propose an extension of this system with one additional dimension, the movement. The combination of this new variable with existing static ones will be studied according to the properties of visual perception.

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Avec le développement d'Internet et de la numérisation, les bibliothèques doivent compléter leur offre classique par des offres d'accès en ligne. Si les bibliothèques traditionnelles garantissent une assistance humaine pour les utilisateurs, un des enjeux des bibliothèques numériques est d'offrir des outils d'interface conviviaux pour explorer, naviguer et comprendre l'espace d'information structuré que constituent les ressources documentaires. Dans ce cadre, la visualisation interactive dispose de propriétés intéressantes comme la perception instantanée de groupes, de relations ou de répartitions, ou encore le contrôle de la représentation dans une boucle action/visualisation. Cet article décrit une suite d'outils interactifs de visualisation cartographique, génériques, paramétrables et combinables entre eux, destinés à fournir une meilleure compréhension des ressources et de leur organisation. Ces outils permettent de représenter des listes d'autorité, des thésaurus, des résultats de requêtes ou des cartographies thématiques de corpus, sous forme d'arborescences, de graphes ou de diagrammes.ABSTRACT. The digital evolution of the last 10 years leads to a real increase of online resources, including digital libraries. In order to guarantee the quality access, librarians classify, describe, document, and catalog their resources. Classic libraries offer human users assistance to apprehend their organization. Then a challenge for digital libraries is to provide efficient and user friendly tools for a deep and shallow navigation. Interactive visualization shows interesting properties for these tasks. Indeed, the vision process includes preattentive perception of groups of entities, relation and repartition; and interaction allows control feedback through the action/visualization loop. This paper describes a set of generic tools providing cartographies using graphs or diagrams to enhance the understanding of libraries resources and organization. MOTS-CLÉS : visualisation d'information, dessin et filtrage de graphes, diagrammes d'Euler.