Volume Rendering of Planet-scaled 3D Atmospheric Data on Virtual Globes

Abstract

Although texture slicing based volume rendering method has been widely used in data visualization, applying it to render atmospheric data that span entire globe has always been a challenging task. The difficulties are threefold. First, conventional volume rendering methods are used to process data referenced in a Cartesian coordinate system, whereas atmospheric data are georeferenced to a geodetic coordinate system. This difference brings about complications in texture sampling. Second, planet-scaled atmospheric data, especially those in high resolution, exacerbate performance issue in rendering time complexity. Third, spherical shaped bounding volume of Earth’s atmosphere makes the calculation of proxy geometry difficult. In this paper, a new method is proposed to tackle the challenges aforementioned. The coordinates of volume vertices and textures are represented in spherical coordinate system to avoid the accuracy loss due to conversion between Cartesian and geodetic coordinate system. The calculation of proxy geometry is worked out. The proposed method is tested by being implemented into a rendering engine visualizing atmospheric data set.