Visualizing Vector Data using Glyph Shapes
|The image shows a novel way to visualize and interpret vector data. The glyph geometries (sphere, ellipsoids, etc) are generated, rendered and manipulated interactively in real time. The snapshot shows the velocity field of a point source earthquake simulation using a novel method of encoding vector information, where the magnitude is shown by size and color of the glyph (ellipsoid) and the direction is shown by the dipole dots (the white and black spots on the poles of ellipsoids represent the head and tail of the vector respectively). Courtesy of Amit Chourasia, San Diego Supercomputer Center, UC San Diego|
Called GlyphSea, the project’s name refers to the use of glyph shapes, such as ellipsoids or spheres, which are marked at each end to allow observers to easily identify both the direction and intensity of the movement. To illustrate the project, SDSC researcher Amit Chourasia and his team at UC San Diego created a narrated video of movements and earthquake visualizations using these glyphs, which have a white dot on the end of the glyphs moving toward the observer’s field of view, and a black dot on those moving away.
The visualization project was recently awarded as part of a four-way tie for second place in the International Science & Engineering Visualization Challenge, a collaboration between the National Science Foundation (NSF) and the journal Science.
“By varying size and color to show magnitude, GlyphSea can display any kind of motion intuitively, from a major earthquake on the San Andreas fault to magnetic turbulence in stars millions of light years from Earth,” said Chourasia, whose team included SDSC graduate research assistant Emmett McQuinn; Jean-Bernard Minster, professor of geophysics with UCSD’s Scripps Institution of Oceanography (SIO); and Jurgen Schulze, an assistant research scientist with the California Institute for Telecommunications and Information Technology (Calit2) at UCSD.
“The strength of this method is that it is not only simple, but very intuitive.” said Chourasia, in noting that the application could potentially be used across a wide range of science domains. “GlyphSea could also be used to render visualizations to display the magnitude and direction of movement within the human body, such as blood flow. That’s because one of GlyphSea’s key benefits is that it can be used to show features at both the macroscopic and microscopic level. Moreover, the application is interactive, where various parameters could be customized and changes could be viewed in real time.”
Referring specifically to the to seisomological visual rendering created by the research team, SIO’s Minster said that GyphSea’s technique of encoding and displaying orientation information of vector data by using procedural dipole texturing is what makes this application so unique.
“This allows seismologists to study the ground motion dynamics at a level of detail not seen before,” said Minster. “We can clearly and easily identify P-waves and S-waves for ground motion using this new method.”
P-waves, or primary waves, are longitudinal or compressional waves and can travel through gases, liquids and solids. S-waves, or secondary waves, are transverse or shear waves, but slower than a P-wave, and can move through solids but not through gases or liquids.
Additional credits for the GlyphSea visualization include Kim Olsen, Steve Day, Geoffrey Ely, and Thomas Jordan of the Southern California Earthquake Center (SCEC). Data Credits include Point Source Simulation by Geoffrey Ely and Emmett Mcquinn; TeraShake Simulation by Kim Olsen and Yifeng Cui (SDSC) et al., SCEC MHD simulation by Alexei Kritsuk and Mike Norman (SDSC), and Sergey Ustyugov (KeldyshInstitute of Applied Mathematics, Russia).
This research was funded through National Science Foundation’s OCI-0636438, EAR-0744493, SCI-0503697, OCI-0503944, OCI-0932251 awards. NVIDIA provided their latest graphics cards during development.
GlyphSea visualization movie: http://visservices.sdsc.edu/projects/scec/vectorviz/glyphsea/movies/GlyphSea-720p-cbr6.mp4