Browsing Zoomable Treemaps: Structure-Aware Multi-Scale Navigation Techniques

Abstract

Abstract-Treemaps provide an interesting solution for representing hierarchical data. However, most studies have mainly focused on layout algorithms and paid limited attention to the interaction with treemaps. This makes it difficult to explore large data sets and to get access to details, especially to those related to the leaves of the trees. We propose the notion of zoomable treemaps (ZTMs), an hybridization between treemaps and zoomable user interfaces that facilitates the navigation in large hierarchical data sets. By providing a consistent set of interaction techniques, ZTMs make it possible for users to browse through very large data sets (e.g., 700,000 nodes dispatched amongst 13 levels). These techniques use the structure of the displayed data to guide the interaction and provide a way to improve interactive navigation in treemaps.

Simulation repository visualisation and exploration

“…approach has been used to visualise different hierarchical data, such as inherently hierarchical organisation structures [5], file systems [6], Usenet newsgroup [7] and so on. Well-known treemap drawbacks are the hierarchy discernment [8] and the fact that the position of the mouse pointer designates an entire branch of the tree [9] because each point belongs to a single leaf node but also to all its ancestors [9]. Of course, one of their advantages is the use of the all available 2D space.…”

“…The user can further explore the simulation repository through the in-depth navigation [9] based on two basic operations: drill-down and roll-up. Drill-down occurs when a user has identified a potentially interesting group of simulations and he/she wishes to explore further details of this group, and so he/she clicks on an ellipse to obtain more details.…”

“…It is not the same for other 2D spacefilling techniques. For instance, in the treemap visualisation technique both nested rectangles and adjacent rectangles have no space between them, so the position of the mouse pointer designates a branch of the tree [9] because each point belongs to a single leaf node but also to all its ancestors [9]. Finally, in the ExploraTool, to obtain the list of simulations within a specific ellipse the user can click directly on the target ellipse.…”

Hoptrees: Branching History Navigation for Hierarchies

“…These employ strategies to make large, complex trees easier to interpret, e.g. specialized zoom techniques [2][3][4] and layout algorithms [5,6]. This work has led to a variety of innovative designs and strategies for presenting the most important information to users and hiding unneeded information, while simultaneously maintaining a sense of location and context within the tree, such as the SpaceTree [7].…”

“…Users can navigate by clicking on either the Gender Browser's icicle plot or nodes in the hoptree, and updates are synchronized between the two widgets. We have released our hoptree implementation as an open-source jQuery plugin that could be applied to a variety of web-based hierarchy browsing applications 3 . The hoptree prototype exposes a simple programming interface for integration with hierarchy browsing applications.…”