GosperMap: Using a Gosper Curve for Laying Out Hierarchical Data

Abstract

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.

State of the Art Exploration Systems for Linked Data: A Review

“…The architecture of the application takes advantages from Model View Controller (MVC) software architectural pattern, it has been built primarily with AngularJS 21 framework, and modules of Jassa library 22 (JAvascript Suite for Sparql Access) are reused. To adopt the interface for datasets, there is no need to understand the core layer of the system.…”

“…The model in MVC contains classes with reference to resources, and a parser to fetch the classes from the resources received 20 http://wiki.openstreetmap.org/wiki/API 21 https://angularjs.org 22 http://aksw.org/Projects/Jassa.html by DBpedia. While controller and view, which are the primary units of the framework, have been designed independently of models so it can be reused with diverse modules.…”

“…The application is built by adopting the efforts of [22] on Gosper Treemaps to Linked datasets with a structure of the hierarchical ontology. Therefore, it transforms entities of the DBpedia dataset to be shown as maps creating a hierarchy of areas along with their ontological class.…”

Interactive Revision Exploration using Small Multiples of Software Maps

“…Besides rectangular tree maps, the voronoi tree map provides an inherently more stable layout algorithm, especially when using an initial distribution of nodes (Hahn et al, 2014). The gosper map provides a more map-like look and a high spatial stability for changing hierarchical data (Auber et al, 2013). An effective use of multiple visualization techniques to examine changes in hierarchies is presented by Guerra-Goméz et.…”

Stenomaps: Shorthand for shapes

“…[40]. Recently, the use of space-filling curves to display hierarchical or complex datasets has gained attention (e.g., [1,37]). In contrast to spacefilling curves, our approach focusses on a curve that covers only a part of the area while still sufficiently describing it.…”