The goal of this project is to investigate the use of visualization software based on the visual programming and data-flow paradigms to meet the needs of the SPOF and through it the International Solar Terrestrial Physics (ISTP) science community. Specific needs we address include science planning, data interpretation, comparisons of data with simulation and model results, and data acquisition. Our accomplishments during the twelve month grant period are discussed below

Goodrich, Charles C.

English

NASA Technical Reports Server

NASA-CR-192 707 
Developrnéit of Visual Programming 
Techniques to Integrate Theoretical 
Modeling into the Scientific 
Planning and Instrument Operations 
Environment of ISTP
6,2i7 
NAG 5-1825 S-i /3/7 
Final Report 
C. Goodrich 
Advanced Visualization Laboratory

University of Maryland 
OeL
	 c.ri 
!ftP 
(NASA-CR-192707) DEVELOPMENT OF 
VISUAL PROGRAMMING TECHNIQUES TO 
INTEGRATE THEORETICAL MODELING INTO 
THE SCIENTIFIC PLANNING AND 
INSTRUMENT OPERATIONS ENVIRONMENT 
OF ISTP Final Report (Maryland 
Univ.) 1.6 p
N93-22004 
Unc 1 as 
G3/61 0153107
https://ntrs.nasa.gov/search.jsp?R=19930012815 2020-03-17T06:26:48+00:00Z
Final Report: 
Development of Visual Programming 
Techniques to Integrate Theoretical Modeling 
into the Scientific Planning and Instrument 
Operations Environment of ISTP 
The goal of this project is to investigate the use of visualization software 
based on the visual programming and data-flow paradigms to meet the needs of 
the SPOF and through it the ISTP science community. Specific needs we address 
include science planning, data interpretation, comparisons of data with simulation 
and model results, and data acquisition. Our accomplishments during the twelve 
month grant period are discussed below. 
2 Accomplishments 
During the first six months of the project we evaluated both AVS and apE 
as candidates for the multi-platform visualization environment on which to base 
our development. We selected AVS as the primary package, as described in our 
six-month progress report. Using AVS, we developed three dimensional displays 
of sateffite trajectories, empirical models of magnetospheric boundaries and fields, 
and field and plasma results from empirical and global MHD models. We began 
exploring mechanisms to allow our system to communicate with other packages, 
1
thereby allowing users to incorporate capabilities of those packages and continue 
to make use of tools they have developed themselves. 
During the second six months of the project we refined our AVS tools, de-
veloped a number of data-comparison capabilities via inter-application commu-
nication with AVS and PV-Wave, incorporated additional ephemeris and key pa-
rameter data sets into our displays, implemented modules to read the GGS CDF 
files directly, and combined all these techniques into several prototype systems. 
We have shown our work to the ISTP.
 community through live demonstrations 
at Science Working Group Meetings, and videotaped animations for distribution. 
Several GGS and CLUSTER investigators have expressed serious interest in it. 
2.1 AVS selected as primary package 
We have determined that AVS is the software package to pursue. We found 
AVS easier to use with a better, more coherent user interface. It has a more 
sophisticated data flow model based on shared memory and socket communication; 
apE used simple pipes for data flow. Finally development of new functions in 
AVS is significantly easier. 
In addition this choice was also determined by the evolution of the orga-
nizations behind AVS and apE. apE changed from an academic package to a 
commercial one marketed by Taravisuals, Inc. This change eliminated a major 
advantage of apE, source code availability for a nominal charge. In a more general 
2
sense, the change highlighted the weaknesses of an academically-based system; 
the inability of the staff at the Ohio Supercomputer Center, with a typically lim-
ited budget, to cope with the large volume of users needing support for apE, a 
quite complex package. 
Equally dramatic institutional changes occurred regarding AVS, but in our 
opinion these actually left AVS in a stronger position. AVS was originally 
developed by Stellar Computer for their line of super-minicomputers. 'After 
merging with Ardent Computer, the new Stardent Computer decided, under 
customer pressure, to port and/or license AVS for other Unix systems, including 
DEC, SUN, HP, and IBM. This decision made AVS a viable candidate for our 
study. Subsequently, Stardent Computer has folded as a hardware manufacturer, 
spawning AVS, Inc. as a software company to develop and support AVS. Since 
then three new versions of AVS , 3.0, 4.0, and 5.0, have been released and 
ported to over 20 more platforms, including supercomputer-class machines from 
six manufacturers. 
AVS, Inc. has also established a strong user support group as well as a ven-
dor AVS consortium. Vendors who are currently members of the AVS consortium 
include: AVS Inc., Convex, DEC, HP, IBM, Kubota Pacific, and Sun. Through 
support by the AVS consortium and the International AVS Users Group, an Inter-
national AVS Center has been established at the North Carolina Supercomputing 
Center, where approximately 500 user-donated modules are available via anony-
3
mous ftp. The JAUG also holds an annual conference. Thus we feel AVS has 
matured into a strong multi-platform visualization package with excellent user 
support. 
2.2 Display of Magnetospheric Boundaries 
Working with Mauricio Peredo, we have developed an AVS module to display 
the empirical models for the magnetospheric boundary layers used by the SSC 
software of the NSSDC to define regions of the magnetosphere for science 
project planning. These are: the bow shock model of Fairfield [Fairfield, 1971], 
magnetopause model of Sibeck [Sibeck et al., 1991], and the neutral sheet model 
of Fairfield [Fairfield, 1971]. This module allows the staff of the SPOF to display 
3D surfaces of these boundaries with interactive control over the parameters of 
the models defining the surfaces. 
At the suggestion of Dan Baker and Ed Hones, we have enhanced the original 
modules to display conceptually the so-called Windsock effect. The new module 
models the effect of a change in the solar wind direction on the magnetospheric 
boundary layers as the change propagates down the magnetosphere. The location, 
angle, and extent of the disturbance can be controlled interactively, producing an 
animated 3D display of the predicted effect. While this display is a simple model 
of the Windsock effect, animations of the model can stimulate serious thought. 
4
2.3 Display of Magnetic Fieldlines 
We have successfully ported to our system Tsyganenko's implementation 
of his 1989 magnetic field model [Tsyganenko, 1989] and reimplemented it as 
an AVS module. This module allows universal-time-coordinated 3D display of 
fleidlines traced from one or more seed points. We have developed displays with 
many fieldlines selected to illustrate large scale features of the Earth's magnetic 
field.
We have also developed the ability to trace the magnetic flux tubes passing 
through spacecraft positions down to the Earth's surface using the Tsyganenko 
89 field model; other field models or MHD simulation results can be easily 
substituted. The position of the corresponding footprints of the flux tubes can 
be seen in relation to the approximate fields-of-view of the ground stations of the 
Canopus array in Canada, shown as red disks. The Earth is represented as a sphere 
with continental outlines. The displays can be easily animated in time, so that the 
system is animated over time, showing magnetic conjunctions of the spacecraft 
and ground stations as they occur. For Example, figure 1 shows the footprint of 
the flux tube passing through IMP-8 with the Canopus stations. This prototype 
demonstrates the usefulness of such systems for science planning activities of the 
SPOF.
5
2.4 Display of Spacecraft Trajectories 
We have developed a set of AVS modules that display in 3D the position 
at a given time and its trajectory before and following that time of a spacecraft 
using data from NSSDC ephemeris files. The positions of several spacecraft can 
be displayed using multiple copies of these modules. Because they are all linked 
to a common universal time variable, their relative positions are accurate. This 
time variable can be easily animated, creating an animation of the motion of sets 
of spacecraft. 
Because of the modular nature of AVS, the boundary layer and field line 
displays can be easily added to the spacecraft trajectory displays. Thus we can 
followthe synchronized motion of several spacecraft in relation to the bow shock, 
magnetopause and neutral sheet. Using the base functions of AVS, the combined 
display can be arbitrarily and interactive rotated, translated, and zoomed (in and 
out). We obtained additional ephemeris data from NASA on other spacecraft and 
the moon. These can be displayed concurrently and in any combination, as for 
example that shown in figure 2. 
2.5 Display of MHD Simulation 
We have explored using AVS to display the results of the MHD code [Lyon 
et al., 1987] used by the University of Maryland Theory investigation to globally 
model the magnetosphere. Our purpose is to develop ways of making the model 
6
results easily available and accessible to all the ISTP investigators. We have 
developed AVS applications that read in the MIII) results, display "cut planes", 
isosurfaces, and vector (arrow) piots of any of the MHD variables. Furthermore 
we have developed an AVS module that will interpolate the MHD data, defined in 
a volume, onto an arbitrary set of points. This module allows us to interpolate the 
MHD results onto a spacecraft trajectory, allowing direct comparison of the MuD 
results with the in situ data collected along that trajectory. We have expanded our 
capabilities for quickly producing such direct comparisons of data and simulation 
results by communicating with other packages, such as PV-Wave or DL, as 
discussed in the next section. 
2.6 Data Display through Inter-Application Communication 
We have chosen to take advantage of the simple yet powerful graphics 
capabilities of PV-Wave to display actual spacecraft data in combination with 
3D display of spacecraft trajectories. This required the development of AVS 
modules that exchange data and communicate with PV-Wave. PV-Wave can 
produce stacked line plots suitable to display the time series data collected by 
spacecraft instruments. In figure 3 we show magnetic field and plasma data from 
IMP-8 during an outbound pass from the magnetosphere to the magnetosheath and 
out into the solar wind. The plots displays are synchronized with the complete 
3D display of the satellite position, trajectory, and the empirical bow-shock, 
7
magnetosphere, and neutral sheet surfaces. Our latest modules use shared-memory 
for efficient data transmission between PV-Wave and AVS, and allow arbitrary 
operations on the data within PV-Wave 
When combined with the module to interpolate MHD results along the same 
trajectory, the display of stacked line plots allows the comparison of simulation 
results with the observed data measured by the spacecraft, or comparison of results 
from different models or numerical simulations, in order to compare models and 
investigate differences. 
2.7 Direct Data Import 
For all of the above applications, the ability to input ISTP and NSSDC data 
into AVS has been key. We have found the extensible nature of AVS has enabled 
us to easily develop a number of modules to read SSC and CDHF data directly 
into our AVS networks. For example, we can now read Key Parameter data 
from CDF files extracted from the ISTP Central Data Handling Facility. This 
also required incorporation of capabilities for handling various spacial coordinate 
systems and differing universal time representations commonly encountered in 
data from multiple sources within NASA and the researchers. In addition to 
simplicity and improved speed, the ability to read the appropriate CDFs directly 
into the AVS network suggests that in future we can take advantage of AVS's 
remote module mechanism to obtain data directly from remote sites over high-
8
6 
speed networks. 
3 Demonstrations 
We have demonstrated the new functions and tools we have developed for 
AVS at several SWG meetings. The real-time demonstrations using Maryland 
workstations have generated significant and increasing interest from the 1ST!' 
community. During the January GGS SWG meeting at NASA GSFC, we hosted 
a site visit to the Advanced Visualization Laboratory by members of the 1ST!' 
mission, including NASA Goddard personnel and investigators from UCSD, 
Lindau, Germany, and France. While it would be unrealistic to enforce a graphic 
standard for the project, we hope that the SWG will see the value of these tools, 
and the ease of developing new ones within AVS. 
Demonstrations of the work have been well received at other conferences, 
including the 3rd Huntsville Workshop on Magnetospheric Plasma Models. 
In addition to these demonstrations, at the request of the Project we assisted 
in supporting the summer IACG meeting in Airlee, Va. We provided computers, 
technical support, and simulation results in order to show the mission planning 
and data analysis tools we are developing in collaboration with the SPOF. We thus 
helped in the planning of the IACG campaigns by displaying in 3D "on the fly" 
the positions of Interball and other spacecraft for the periods being considered.
In addition to live demonstrations, we have produced video animations on 
space science data analysis and mission planning tools. These were shown and 
very well received at the January GGS SWG meeting at NASA GSFC. In response 
to many requests, we produced a revised video with voice-over for reproduction 
and distribution to NASA researchers.
10
References 
Fairfield, D., Average and unusual locations of the earth's magnetopause and bow 
shock, J. Geophys. Res., 76, 6700, 1971. 
Fairfield, D., A statistical determination of the shape and position of the geomag-
netic neutral sheet, J. Geophys. Res., 85, 775, 1980. 
Goodrich, C., R. Kulkarni, D. McNabb, and M. Peredo, Interactive Tools for 
ISTP: Science Planning and Data Analysis, Video tape: AVL and NASA/GSFC, 
8 minutes, February, 1993. 
Lyon, J. G., J. A. Fedder, and J. D. Huba, The Effect of Different Resistivity 
Models on Magnetotail Dynamics, J. Geophys. Res., 91, 8057,1986. 
Sibeck, D., R. Lopez, and E. Roelof, Solar Wind control of the magnetopause 
shape, location and motion, f. Geophys. Res., 96, 5489, 1991. 
Tsyganenko, N. A., On the Redistribution of the Magnetic Field and Plasma in 
the Near Nightside Magnetosphere during a Substorm Growth Phase, Planet. 
Space Sci., 37, 183, 1989
11
Appendix B Figure Captions 
Figure 1. Magnetic conjunction of flux tube through IMP-8 with Canopus station, 
Tsyganenko 1989 model. 
Figure 2. Spacecraft and moon trajectories with magnetospheric boundary layer (half) 
surfaces: bow shock, magnetosphere, neutral sheet. 
Figure 3. IMP-8 magnetic field and plasma data on outbound pass from magnetosphere 
to magnetosheath, plotted by PV-Wave/AVS module. 
12
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Development of visual programming techniques to integrate theoretical modeling into the scientific planning and instrument operations environment of ISTP

Development of visual programming techniques to integrate theoretical modeling into the scientific planning and instrument operations environment of ISTP

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