A Simple Implementation of a 3D Data Cube Viewer

One of the most important end products from a spectral line observation is the brightness B as a function of right ascension alpha, declination beta and frequency omega. The B(alpha, beta, omega) is commonly referred to as a data cube or an image cube. In practice, brightness is obtained, for each frequency channel separately, as images. While rendering a stack of such images in various ways can illuminate the important aspects of a data cube, the process of finding relations between channels can be difficult and time consuming. New instruments, such as ALMA and EVLA, which can observe over a broad wavelength range and thousands to millions of channels, will present enormous challenges for the visualization and analysis of large numbers of paged images. It is often desirable to render the data cube as a whole to examine it from arbitrary viewing angles and for any clip region of interest. To meet some of these needs in CASA, we developed a GUI program, called 3v, based on the Qt OpenGL module for viewing 3D data.