Significant accomplishments in the past year are presented and include the following: (1) enhancements to VIS-5D; (2) Implementation of the VIS AD System; and (3) numerical modeling applications. Focus of current research and plans for next year in the following areas are briefly discussed: (1) continued development and application of the VIS-AD system; (2) further enhancements to VIS-5D; and (3) plans for modeling applications

Hibbard, William L.

Tripoli, Gregory J.

English

NASA Technical Reports Server

N93-20070
TITLE: Interactive Access and Management for Four-Dimensional Environmental Data Sets Using McIDAS
INVESTIGATORS: William L. Hibbard and Gregory J. Tripoli
BACKGROUND OF THE INVESTIGATION:
The development of MclDAS (Man-computer Interactive Data Access System) has been a long term
project at the Space Science and Engineering Center for managing, displaying and processing earth science
data. This grant is part of a series of NASA funded projects to explore technological opportunities to extend
the capabilities of the McIDAS system, including animated three-dimensional displays, the use of computing
standards such as UNIX and X Windows, the use of commercial workstations, interactive three-dimensional
graphics, graphical user interfaces, and visual interaction with computations. The systems developed by these
NASA funded projects have either become part of McIDAS, or access data in McIDAS file formats.
The McIDAS-X system released in April 1992 evolved from an experimental version of McIDAS
running under UNIX and X Windows, and developed by this NASA funded technology exploration. The
VIS-5D (VISualization of 5-Dimensional data sets) system, available as freeware and widely used by
atmospheric modelers, was developed as part of this NASA funded technology exploration. VIS-5D provides
highly interactive visual exploration of large data sets in McIDAS grid files, such as those produced by
numerical simulations and volume scanning radars. The user interface of VIS-5D is specifically designed for
earth scientists and, for a given size of workstation, it allows exploration of much larger data sets than other
visualization packages.
VIS-5D is being used by scientists at UW-SSEC as a routine diagnostic tool for their model
developments, and has had a real effect on the content of their science. It is also being used by scientists at
NASA/MSFC and at NASA/GSFC. In addition to the support from NASA for the development of VIS-5D,
the French Meteorology Bureau and INPE/CPTEC in Brazil have both funded visiting scientists for periods of
six months who contributed to its development.
We have implemented a distributed version of VIS-5D, supported by the Gigabit Testbed Project. This
version of VIS-AD accesses very large data sets (10 ^ 10 grid points) residing on remote super computers,
although it requires extraordinary computational and communications resources.
The current NASA grant combines support for this exploration of technology with support for
atmospheric modeling, recognizing the importance of cooperation between scientists and system developers.
SIGNIFICANT ACCOMPLISHMENTS IN THE PAST YEAR:
Enhancements to VIS-5D
During the last year, enhancements to VIS-5D include
A) a significant decrease in the response time to user selection of new iso-level contour surfaces for
depicting fields
B) the ability to render plane slices as pseudo-colored images, which is useful for visualizing highly
textured radar data
C) the ability to render topographical map backgrounds from user-supplied topography data files
D) a port of VIS-5D to run on almost all models of SGI workstations
E) a port of VIS-5D to run on the IBM RISC 6000 workstations.
Implementation of the VIS-AD system
We have implemented an initial version of the VIS-AD (VISualization for Algorithm Development)
system and have demonstrated it at the American Meteorological Society conference in Atlanta in January
1992. VIS-AD lets scientists visualize the results of experiments with their algorithms. It functions somewhat
like an interactive debugger, except that it presents graphics of high-level data objects rather than just printing
lists of numbers. Its focus is on tracing high-level algorithm behavior rather than on tracking down low-level
bugs. VIS-AD provides
A) an editor, compiler and interpreter for a programming language similar to C
B) management of user-defined data structures, accessible as data objects from the programming language
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https://ntrs.nasa.gov/search.jsp?R=19930010881 2020-03-17T08:20:16+00:00Z
C) support for MISSING data in the programming language
D) an elegant and flexible mechanism for managing finite samplings of continuous quantities, such as the
way a satellite image samples earth locations
E) interactive execution controls for setting breakpoints and executing single steps in programs
F) a means to display any combination of data objects in a program.
Scientists at Wisconsin are beginning to use VIS-AD to help them develop algorithms for the GOES
Pathfinder project. VIS-AD accesses image data and gridded data in MclDAS data files, so that it can easily
be used to access data from the GOES archive and other sources at SSEC.
In order to demonstrate the flexibility of VIS-AD, we have applied it to an algorithm for discriminating
clouds in GOES images using infrared and visible data. These image data may be displayed as pseudo-colored
images, as two-dimensional contours of pixel values, as three-dimensional surfaces, as two- and three-
dimensional scatter diagrams of infrared temperature versus visible brightness versus variance of temperature,
and as other formats. These display formats are not hard-wired, but are defined by the user in a flexible
language.
Numerical Modeling Applications
The University of Wisconsin Regional Atmospheric Modeling System (UW-RAMS) is being used as a
prototype model to test the usefulness of VIS-5D to numerical simulation. The output infra-structure of the
UW-RAMS model output was modified to write output of any variable or function within in a large menu of
possible functions, to MclDAS grid format where it could be easily picked up by the VIS-5D software for
immediate visualization of results. Model output formats for numerical model runs on non-MclDAS
computers was also modified to create files which are easily converted to MclDAS files for VIS-5D
applications.
As a result, essentially all numerical model runs are capable of being visualized routinely, and most, in
fact, are. The visualization has become a primary tool for understanding complex dynamical systems.
Problems encountered with the prototype visualization software are relayed to the Hibbard-Paul development
group, where improvements are made. The visualization has used also for presentation graphics for
publication, at conferences, seminars and even graduate student exams. Several examples of its use as an
interactive model diagnostic tool and then as a presentation graphics tool are
mentioned below.
As an interactive diagnostic tool, the VIS-5D has become a software of central importance. Both
numerical studies of tropical cyclogenesis and polar low cyclogenesis used VIS-5D to investigate the details of
scale interaction processes, by finding and defining the existence and movement and vertical trapping of
outward and inward propagating spiral gravity wave bands, showing the development of a hurricane eye
structure, the coexistence of microphysical quantities, the relationship between isentropic surface and
momentum surfaces throughout the storm with regard to the existence of conditional symmetric stability, the
development of the Ekman boundary layer and so on. Trajectory analysis has been useful in revealing major
differences between the dynamical structure of the tropical cyclone at the tropical depression, storm and
hurricane stages.
Numerical studies of large eddies in the boundary have used the VIS-5D to demonstrate the tendency
toward organized bands in unlikely situations, The animation instills the viewer with a sense of how and why
the organization must occur and on what it must depend.
Numerical studies of thunderstorm clouds with UW-RAMS have utilized VIS-5D to depict the updraft
organization, existence and development of the mesocyclone and the role of the different microphysical
components of the system. Numerical studies of downbursts by Dr. J. Anderson have also utilized VIS-5D to
visualize downbursts simulated by an independent model.
The VIS-5D graphics have been employed as a tool for conveying the simulated dynamics to an
informed audience at scientific conferences. Presentations of the visualized hurricane at the Miami National
hurricane conference and the Atlanta Mesoscale conference were well received and enabled the speaker to
demonstrate dynamical principles of scale interaction otherwise difficult to understand or explain. The
visualized hurricane was also used in the classroom to explain hurricane dynamics to a senior level
undergraduate class.
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Thevisualizedpolarlow simulationwaspresentedattheAtlantamesoscaleconferenceto demonstrate
the influenceof inertialstabilityonCISKinducedarcticcyclogenesisandwassuccessfulindrivinghome
pointswhichwouldhavedifficultto showwith two-dimensionalgraphics.Severalpapershavebeensubmitted
or in preparationutilizingfull coloror grayshadedVIS-5Dillustrations.
FOCUS OF CURRENT RESEARCH AND PLANS FOR NEXT YEAR:
Continued development and application of the VIS-AD system
Because of its ability to display user-defined data structures and because of its support for user-written
algorithms accessing those data structures, VIS-AD is an extremely flexible tool for visualizing data and
algorithms. It is the appropriate software context for most further work under this NASA sponsored
exploration of technology. The development of VIS-AD replaces our earlier plans for continued development
of VIS-GI and for providing interactive diagnostics as part of VIS-5D. The most immediate areas for
continued development of VIS-AD include
A) labeling display axes with application values
B) labeling the current frame in an animation sequence with application values
C) supporting a variety of map projections
D) supporting satellite navigation and calibration
E) extending the library of intrinsic functions for image processing
F) implementing MclDAS commands as intrinsic functions
G) supporting user-written external functions written in C or Fortran
H) improving the efficiency of the language interpreter
I) providing a translator from the VIS-AD language to C.
We will also continue to support scientists at Wisconsin and at NASA who apply VIS-AD to their
algorithm development problems, such as those developing product generation algorithms for GOES
Pathfinder.
Further enhancements to VIS-SD
We will respond to scientists' needs to make VIS-5D more useful for exploring atmospheric simulation
data sets. Some possible new features include
A) interactive retrieval of field values using the 3-D cursor
B) providing more flexible map projections in the 3-D box.
o Plans for ModelingApplications
We plan to continue to utilize the Stellar GS-2000 as a primary modeling workstation and to utilize the
visualization capability both for locally run model simulations and runs made on other machines. In this
coming year, we will be simulating much more real data including an observed mid-latitude snow storm, the
killer tornado of Plainfield, Illinois and several mesoscale convective complexes including one with a strong
Derecho. We will also accelerate the tropical cyclone research to investigate external scale interactions with
the surrounding circulations and again, VIS-5D will play a central role. In addition, we are beginning plans to
develop an operational model of mesoscale weather for which there will be application of VIS-5D. Most likely,
VIS-5D will be used as a presentation tool in many more conference papers and publications since we have
learned to depend on its presentation power. Because the quality of the presentation and published presentation
graphics is a permanent record of the VIS-5D product, we would strongly suggest that the development of
VIS-5D should be continued to improve the appearance of the visualizations under these circumstances.
PUBLICATIONS:
Aune, R., G. Callan, and W. Hibbard, 1991; A 4D visualization of a 4D assimilation system. Preprint, 9th
Conference on Numerical Weather Prediction, Oct. 14-18, Denver, AMS, 614-615.
Hibbard, W., and B. Paul, 1991; El Nino Satellite Observations and Downburst Simulation. SIGGRAPH
Video Rev., No. 74.
13
Hibbard,W., 1991;Access- enduser(scientist)viewandenvironmentsubgroup.Partof theSIGGRAPH'90
workshopreport:Datastructureandaccessoftwarefor scientificvisualization.EditedbyLloyd A.
Treinish. ComputerGraphics25(2),104-118.
Hibbard,W., 1992;A highlyparallelapproachfor satellitearchiveprocessing.Preprints,Conf.Interactive
InformationandProcessingSystemsfor Meteorology,Oceanography,andHydrology.Atlanta,AMS,82-
83.
Hibbard,W., C. DyerandB. Paul,1992;A developmentenvironmentfor dataanalysisalgorithms.Preprints,
Conf.InteractiveInformationandProcessingSystemsfor Meteorology,Oceanography,andHydrology.
Atlanta,AMS, 101-107.
Tripoli, G.J., 1992;An explicitthree-dimensionalnon-hydrostaticnumericalsimulationof atropicalcyclone.
Meteor.in Atmos.Phys.,acceptedfor publication.
14
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Interactive access and management for four-dimensional environmental data sets using McIDAS

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