This special issue features the best articles that were selected from the 19th SPIE Conference on Visualization and Data Analysis (VDA 2012). This annual conference is a major international forum for researchers and practitioners interested in data visualization and analytics research, development, and applications. VDA 2012 was held in the city of Burlingame outside San Francisco, California, during 23–25 January 2012. VDA 2012 received 50 high-quality submissions from around the world. In total, 24 articles were selected for full conference articles. Of the top eight articles that were invited for this special issue, six were expanded and reviewed. The following is a synopsis of these articles. In ‘‘Designing a better weather display,’’ Colin Ware and Matthew Plumlee describe a set of interactive weather displays that depict two meteorological scalar fields and the wind vector field. They evaluate the effectiveness of their approach by implementing three alternative representations each showing the temperature, atmospheric pressure, wind speed, and wind direction simultaneously in one display. By taking advantage of the fragment shader on the graphics card, they first map a combination of scalar fields to color and texture. Then, additional layers of weather and geographical data are rendered on top of the base color layer. In ‘‘A new approach to interactive viewpoint selection for volume data sets,’’ Han Kim and colleagues introduce a new algorithm for finding the best view direction for volume rendering. Their viewpoint selection algorithm is very fast and takes less than a second, which makes it attractive for interactive volume visualization. The key features that make their algorithm fast are the simplicity of their algorithm and an efficient implementation on the graphics card. In ‘‘Animating streamlines with orthogonal advancing waves,’’ Chih-Kuo Yeh and his coauthors present a new flow visualization technique that depicts dense, accurate visualization of complex real-world flows using animated streamlines of an elegant placementcoupled visually appealing orthogonal advancing waves. Their work is motivated by the self-animating image of flow through repeated asymmetric patterns (RPA), which is an innovative approach for creating illusory motion using a single image. They introduce a smooth cyclic variable-speed RPA animation model that emulates orthogonal advancing waves from a geometry-based flow representation. In ‘‘Visual sentiment analysis of customer feedback streams using geo-temporal term associations,’’ Ming Hao and her colleagues present a business intelligence visualization tool that analyzes customer feedback streams harvested from both commercial product web surveys and Twitter. The tool provides four different visualization techniques for sentiment analysis, term association analysis, self-organizing map analysis, and geo-based association analysis. In ‘‘Exploring biological data: mappings between ontologyand cluster-based representations,’’ Ilir Jusufi and colleagues present a new visualization that combines the strengths of hierarchical clustering and ontologies into one analytical platform to study highthroughput data in biology and medicine. This article gives a detailed discussion on system architecture and