Animated Wordle For Time-Varying Text Visualization

As large quantities of text data continue to emerge on the Internet,traditional text reading can no longer satisfy people's requirements of absorbing information.Text visualization which expresses text data in visual interactive graphics,enables people to visually explore the underlying information of the documents with various interactions.Word clouds,as a very popular text visualization technique,can summarize the text content and provide people with a pleasant observation experience.They are widely used in demonstration conditions.Most existing word clouds researches focus on processing and displaying one single document,while few can effectively deal with the time-varying text that contains multiple related documents.Animation is an effective representation of dynamic data and is often considered to be vivid and attractive.Recent years animation is often used to present dynamic relations,spatio-temporal data and graphs.In this paper,we present AniWordle,a new technique to create animated wordle that combines the benefits of animation and Wordle,for visualizing time-varying text data.We generate a compact and stable layout while reducing word crossings during animated transitions by making use of the word size changes that are complementary.According to current popular word clouds and related research,we proposed three design guidelines for time-varying word clouds:compact layout,stable words,fewer crossings.Then we designed the AniWordle algorithm that automatically generates dynamic word clouds.We hierarchically pack words into a set of SCAPs(size-change-aware package)to save space and stable words.Through inter-SCAP and intra-SCAP arrangement,we generate animations with compact layouts,proper.emphasis and smooth transitions.For inter-SCAP arrangement,we consider the space occupancy ratio and the maximal word weight of each SCAP.For intra-SCAP arrangement,we position words according to their weights along time steps.AniWordle can further tighten the layout of each keyframe by applying SCAP-based rigid body dynamics.This algorithm can be extended to create animated phrase clouds.We then designed an interactive generation system based on the AniWordle algorithm.The system provides several samples and allows users to import local time-varying data.After generating the initialized layout,the user can modify the font,color palette,word sizes to customize their word clouds.We also present two forms of evaluation:a comprehensive comparison of AniWordle's results against the state-of-the-art word clouds for visualizing multiple documents,and user studies conducted to understand user preferences among three variants of animated wordle.AniWordle achieved a better balance between compactness and stability compared to dynamic word clouds and context preserving word clouds.Our user study participants favored the variant of AniWordle that sacrifices stability for higher compactness.To further explore the perception of animated wordles,we interviewed participants and collected their detailed feedbacks.