| Multiresolution Visualization and Analysis of Turbulence using VAPOR |
| Alan Norton | |
| NCAR/CISL | |
| Boulder, CO USA | |
| Turbulent Theory and Modeling: | |
| GTP Theme-of-Year Workshop February 28, 2008 |
| Outline |
| VAPOR project overview | ||
| VAPOR technical capabilities (new 1.2 release) | ||
| Interaction techniques for understanding massive turbulence datasets | ||
| Six techniques that have been developed through scientific use of VAPOR | ||
| Visualization is a data exploration process | ||
| Lessons and future work | ||
| VAPOR project overview |
| VAPOR is the Visualization and Analysis Platform for Oceanic, atmospheric and solar Research | ||
| Problem: Because of the recent growth in supercomputing performance, scientific datasets are becoming too large to interactively apply analysis and visualization resources. | ||
| Goal: Make it easier to analyze and visualize massive (Terabyte and greater) datasets | ||
| Provide interactive data access | ||
| Develop user interface customized for scientists | ||
| VAPOR is funded by NSF ITR: a collaboration with NCAR, UC DavisÕ Institute for Data Analysis and Visualization, and Ohio State UniversityÕs Dept. of Computer and Information Sciences | ||
| VAPOR Technical Approach |
| Key components | |||
| Multiresolution data representation, enables interactive access: | |||
| Entire dataset available at lowered resolution | |||
| Regions of interest available at full resolution | |||
| Prioritize ease-of-use for scientific research | |||
| Integrate visualization and analysis, interactively steering analysis while reducing data handling | |||
| Exploit power of GPU | |||
| Principal Capabilities of VAPOR 1.2 |
| New features in version 1.2 (Oct 2007) | ||
| Isosurfaces | ||
| Interactively generated using GPU | ||
| Spherical grid rendering (prototype) | ||
| Support for WRF (and terrain-following grids) | ||
| Existing features: | ||
| Flow integration | ||
| Both steady and time-varying flow integration | ||
| Field line advection | ||
| Volume rendering | ||
| Interactive color/transparency editor | ||
| Interactive control of region size and data resolution | ||
| Bidirectional integration with IDL¨ for analysis | ||
| Data probing and contour planes | ||
| Interactive flow seed placement | ||
| Animation of time-varying data | ||
| VAPOR data exploration examples |
| Combining visualization with analysis of a vortex, in a solar hydrodynamic simulation (Mark Rast) | |
| A Ôcurrent rollÕ in a multi-terabyte MHD dataset (Pablo Mininni) | |
| Advection of magnetic field lines in a velocity field (Pablo Mininni) | |
| Advance of cold air mass in Georgia, April 2007 (Thara Prabhakaran) |
| VAPORÕs Interaction
Techniques for Understanding Massive Turbulence Datasets |
| Interactive feedback is key to visual data understanding | ||
| Multiresolution data browsing | ||
| Enables interactive access to terabyte datasets | ||
| Visual color and opacity editing with histograms | ||
| Identify features of interest by color and opacity | ||
| Export/import data to/from analysis toolkit | ||
| Currently supporting IDL¨ | ||
| Use planar probe for visual flow seed placement | ||
| Local data values guide seed placement | ||
| Track structure evolution with field line advection | ||
| Time-evolution of structures shown by field line motion | ||
| Use the GPU for interactive rendering | ||
| Cartesian, Spherical, Terrain-following (WRF) grids | ||
| Interaction Technique 1:
Multiresolution data browsing |
| Enabled by wavelet data representation | |
| Interactively visualize full data at low resolution | |
| Zoom in, increase resolution for detailed understanding |
| Interaction Technique 2:
Visual color/transparency editing |
| Design developed with Mark Rast | |
| Drag control points to define opacity and color mapping | |
| Histogram used to guide placement | |
| Continuous visual feedback in 3D scene |
| Interaction Technique 3:
Export/import data to/from analysis toolkit |
| Currently using IDL¨ | |
| User specifies region to export to IDL session | |
| IDL performs operations on specified region | |
| Results imported as new variables in VAPOR |
| Interaction Technique 4:
Use planar probe for visual flow seed placement |
| Useful to place flow seeds based on local data values | |
| Planar probe provides cursor for precise placement in 3D | |
| Field lines are immediately reconstructed as seeds are specified |
| Interaction Technique 5:
Track structure evolution with field line advection |
| Animates field lines in velocity field | |
| Useful in tracking evolution of geometric structures (e.g. current sheets, flux tubes) | |
| Based on algorithm proposed by Aake Nordlund | |
| Interaction Technique 6:
Use the GPU for interactive data rendering |
| Modern GPUÕs are cheap, fast, effective | ||
| GPUÕs are SIMD clusters, efficiently traverse data arrays | ||
| Support for cartesian, spherical, terrain-following grids | ||
| VAPOR Lessons |
| Multiresolution methods are essential for understanding massive data sets. | ||
| Interactive analysis and visualization can indeed enable or accelerate scientific discovery | ||
| One-on-one interaction between scientists and software developers results in valuable interaction techniques | ||
| We are only beginning to exploit the power of GPUÕs | ||
| Largest obstacles: | ||
| Wide diversity of data representations used in research | ||
| Data conversion effort | ||
| VAPOR Plans |
| New features prioritized by the VAPOR steering committee and user input | ||
| Features under consideration include: | ||
| Mapping of variables to isosurface color/opacity | ||
| Support for 2D data | ||
| Image-based flow visualization | ||
| Perform math operations on data | ||
| Keyframing and spin animation | ||
| Parallel data conversion on supercomputers | ||
| Wavelet data compression | ||
| Send suggestions to vapor@ucar.edu | ||
| Slide 16 |
| Acknowledgements |
| Steering Committee | ||
| Nic Brummell - CU | ||
| Yuhong Fan - NCAR, HAO | ||
| AimŽ Fournier – NCAR, IMAGe | ||
| Pablo Mininni, NCAR, IMAGe | ||
| Aake Nordlund, University of Copenhagen | ||
| Helene Politano - Observatoire de la Cote d'Azur | ||
| Yannick Ponty - Observatoire de la Cote d'Azur | ||
| Annick Pouquet - NCAR, ESSL | ||
| Mark Rast - CU | ||
| Duane Rosenberg - NCAR, IMAGe | ||
| Matthias Rempel - NCAR, HAO | ||
| Geoff Vasil, CU | ||
| Developers | ||
| John Clyne – NCAR, CISL | ||
| Alan Norton – NCAR, CISL | ||
| Kenny Gruchalla – CU | ||
| Victor Snyder - CSM | ||
| Research Collaborators | ||
| Kwan-Liu Ma, U.C. Davis | ||
| Hiroshi Akiba, U.C. Davis | ||
| Han-Wei Shen, Ohio State | ||
| Liya Li, Ohio State | ||
| Systems Support | ||
| Joey Mendoza, NCAR, CISL | ||