  Rapidly growing virtual reality (VR) technologies and techniques have gained
importance over the past few years, and academics and practitioners have been
searching for efficient visualizations in VR. To date, emphasis has been on the
employment of game technologies. Despite the growing interest and discussion,
visualization studies have lacked a common baseline in the transition period of
2D visualizations to immersive ones. To this end, the presented study aims to
provide a systematic literature review that explains the state-of-the-art
research and future trends on visualization in virtual reality. The research
framework is grounded in empirical and theoretical works of visualization. We
characterize the reviewed literature based on three dimensions: (a) Connection
with visualization background and theory, (b) Evaluation and design
considerations for virtual reality visualization, and (c) Empirical studies.
The results from this systematic review suggest that: (1) There are only a few
studies that focus on creating standard guidelines for virtual reality, and
each study individually provides a framework or employs previous studies on
traditional 2D visualizations; (2) With the myriad of advantages provided for
visualization and virtual reality, most of the studies prefer to use game
engines; (3) Although game engines are extensively used, they are not
convenient for critical scientific studies; and (4) 3D versions of traditional
statistical visualization techniques, such as bar plots and scatter plots, are
still commonly used in the data visualization context. This systematic review
attempts to add to the literature a clear picture of the emerging contexts,
different elements, and their interdependencies.
