VISUAL UNIVERSE

DATA INTO INSIGHT

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TABLE OF CONTENTS

I. Introduction
II. Visualization and scientific visualization defined
III. Forms of visualization
IV. Applications of visualization
V. Visualization production
VI. The future of visualization
VII. Conclusion

It is the purpose of this educational booklet to investigate the topic of visualization in scientific exploration and the presentation of scientific findings. Of importance in this discussion are answers to the following questions:
1. What is visualization/scientific visualization?
2. What are the different forms or media used in visualization presentations?
3. Why is visualization used?
4. How are visualizations produced and rendered?
5. Who are the clients or customers who use or need visualization?

When asked the question, “what is visualization,?” what would be your reply? Has a teacher or other person ever asked you to close your eyes and “visualize” in your “mind’s eye” what something looks like? You might also be asked to “use your senses” with your eyes closed to picture something and ponder it. Try this simple activity. You will need to have someone read this to you in order to do the activity. Close your eyes and imagine this scenario. You are sitting under a willow tree by a quiet, babbling brook at 5:00 P.M. in a valley near Hagerstown, Md. on a sunny June day. There are butterflies hovering nearby, but they will soon be relaxing in their evening respite. As you read your favorite science fiction novel, the day begins to disappear as sunlight refracts splendidly into a glorious sunset. The brilliant hues of red, orange and yellow begin to erase the brilliant blue sky and your mind takes in the resplendent nature show before you. Suddenly, the sky begins to darken as gray clouds roll in, obscuring the beauty and changing nature’s panorama. Wind gusts cause the pages of your book to flip wildly as you begin to run toward the safety of the nearby waiting vehicle. As you enter the automobile, you see before you a tremendous bolt of blue/white lightning, devouring the tree which only minutes before gave you refuge from the warm sunlight. The ground shakes and rumbles and the sounds of crackle and pop and boom are deafening. Nature has once again claimed the inalienable right to change all, and to subject its inhabitants to its frolics and whims. You marvel that you are such a tiny part of this incredible phenomenon called life on the great water planet, Earth.

Were you able to “see” sights and “hear” sounds in your mind without actually seeing and hearing them? Hopefully the answer is affirmative. The human mind has an incredible ability to store and retrieve information from the 3-D (three dimensional), colorful world in which we live. One recalls the phrase that “a picture is worth a thousand words” and remembers times when teachers scurried to the black or white board to draw or illustrate via pictures a concept which was not well captured by students with oral description. Imagine an architect or builder describing to you how your soon-to-be built new home will look without ever showing you a blueprint, artist’s rendering, or drawing. Add lovely pictures and schematics and trees and landscaping in vivid color and you might be inclined to buy. We live, work and play in a visual world. We best understand by using our senses to discern how and why our world works as it does. This begins to sound like the “tools” of science--and so it is.

Back to the original question of “what is visualization?”, it is interesting to note that when these authors asked five NASA employees (scientists, computer programmers, journalists, artists) the definition of “visualization,” we received five different answers. The range of definitions included visualization as “any image which allows the observer to use visual sight to clarify the world,” to “the use of visual images to assign meaning to vast stores of data collected by varied instruments, particularly computers.” One scientist noted that visualization takes huge amounts of data (e.g from satellites) and turns it into credible information which can then be interpreted by humans into meaningful insights. One very simple example of the insight provided by visualization might be the use of graphs. Certainly it is easier to discern patterns in data sets by graphing them. Consider an example of yearly rainfall in a given region over a period of time. Daily rainfall data is accessible but is not easily understood until graphed. At that point average rainfall in one location can then be compared with a second location to see worldwide patterns. This type of information becomes very meaningful when studying phenomena such as El Niño weather patterns. It is even possible to “overlay” information in order to better understand an event such as El Niño. An excellent example of this process may be found here (http://nsipp.gsfc.nasa.gov/enso/nino/stacknino.mov).


The remaining sections of this project investigate how and why visualization is used by countless people for many reasons.

One visualization project from the University of Georgia, (http://tapioca.ismsc.sc.usp.br/~vtk/visgoals/visgoal2.htm)
provides the following definition of visualization:

“The classical definition of visualization is as follows: the formation of mental visual images, the act or process of interpreting in visual terms or of putting into visual form. A new definition is a tool or method for interpreting image data fed into a computer and for generating images from complex multi-dimensional data sets.”

“Visualization is an old term which has received a large amount of interest in the computer science community. Visualization has previously been defined as the ‘formation of visual images; the act or process of interpreting in visual terms or of putting into visual form.’ More recently a new definition has been added: ‘A tool or method for interpreting image data fed into a computer and for generating images from complex multi-dimensional data sets.’”

Another definition presented at a NASA internet site defines data visualization as “exploring large amounts of raw data visually through the use of image processing and computer graphics in order to gain understanding and insight into the data.”
http://dval-www.larc.nasa.gov/DVAL/Capabilities/Datavis/index.html

Perhaps most simply stated, visualization is the process of representing abstract scientific data as images that can assist in our understanding of the meaning of that data. Those images may be as simple as a line, pie, or bar graph, or as complex as a computer generated simulation or model. In any case the human mind and eye want to derive visual meaning out of complex or abstract data in order to make sense out of it. We know that approximately 50 % of the human brain has neurons which assist with vision input and processing. Thus it makes sense that visualization helps us to gain insight by using our vast stores of visual machinery. Let your eyes process the following “visualization:”

This drawing is accompanied by a definition of data visualization and analysis as “Exploring large amounts of raw data visually through the use of image processing and computer graphics in order to gain understanding and insight into the data.”

Other added dimensions of visualization include why we need visualization and what is driving our need for better visualization techniques and products? The “why” is to simply better understand and interpret our world and the universe. The momentum driving this process includes improved computer capabilities which allow many scientists to produce high quality graphical images. Recently more powerful computers with, for example UNIX-based graphics workstations, have allowed great advancement in visualization applications. Additionally, tremendous amounts of data are being collected and processed by satellites, other instrumentation, and tremendous supercomputers. This data is collected and stored in magnetic computer tape files in huge warehouses. Of what use is this mountain of data if it cannot be analyzed and presented in an understandable and meaningful format? Voila!.....visualization to the rescue!

It is interesting that in interviewing several Earth/Space scientists there was a difference of opinion about the significance of visualization to each of their scientific analyses and outcome products. One stated that he prefers to look at Level 1 or 2 data (closer to original form coming from satellites), and that he relies much more on graphs than on images. Another scientist noted that he uses the images to gain better insight, to see patterns and anomalies, and to generate further hypotheses. A third scientist, involved in computer simulations and modeling, emphasized that he would not be able to understand the vast data sets without first using the computer to make simulations or models. Once those models are created, the scientist can discern flaws in the model and can continue to use and interpret data to correct those discrepancies. One recurring theme mentioned by all scientists interviewed was that advanced visualization techniques assist in discovering patterns of behavior in data over time. The use of various visualization forms depends upon user preference, purpose of the visual outcomes, audience to be addressed, and ability to present data in the most accurate and meaningful way. Professionals in a NASA visualization lab agree that most elaborate scientific images (e.g. hurricane satellite images and weather patterns ) are created for the public and not for professional scientists. We cannot, however underestimate the role of visualization in aiding scientists. One internet source summarizes this well in saying:
“’The purpose of [scientific] computing is insight, not numbers.’”
“’The goal of Visualization in [scientific] computing is to gain insight by using our visual machinery’ A significant difference between this application of visualization versus presentation graphics it that the primary purpose, at least initially is for the scientific investigators to use visualization techniques to understand their own data, rather than presenting it to others. The presentation mode comes later in the process”
http://tapioca.icmsc.sc.usp.br/~vtk/visgoals/visgoal2.htm

Historically visualization techniques have been used for many centuries. The Chinese used maps since the early twelfth century. Early forms of visualization included maps, data plots/graphs, and science drawings. With the development of computers, computer graphics were used to study scientific problems. Today the expanded capabilities of computers have propelled scientific visualization to new heights. Scientific visualization uses computer imaging to understand data which is obtained through either physical measurement or simulation. The tools and techniques of scientific visualization allow scientists to derive knowledge and meaning from huge sets of data and the resulting simulations and computations.While the end product is human insight, information must be accessed, processed, and displayed in a meaningful format. Visualization allows scientists to form a hypothesis, gather appropriate data, and verify the original hypothesis or identify new hypotheses from the outcomes.

The term computer graphics is somewhat vague. Scientific visualization via computer generated images can be portrayed as:

Pictures...
GOES East latest visible image of North America
http://www.ssec.wisc.edu/data/east/latest_eastvis.gif

Graphs...
SeaWiFS Spectral Data
http://seawifs.gsfc.nasa.gov/SEAWIFS/IMAGES/SPECTRAL.html

3D images presented in 2D form...
Mars 3-D MOLA Image
http://svs.gsfc.nasa.gov/imagewall/MOLA.html

Home Earth
http://globe.gsfc.nasa.gov/globe/en/gallery/HomeEarth_l.gif



Color images
GOES 8 Color Image of North America
http://rsd.gsfc.nasa.gov/goese/autogvar/goes8/hurricane_big/color/0000_latest.jpg

Models/simulations
http://svs.gsfc.nasa.gov/imagewall/UARS/instruments.html

Animations
1997-98 El Nino
http://sdcd.gsfc.nasa.gov/ESS/images2/nino.mov

Movie loops
http://sdcd.gsfc.nasa.gov/ESS/images2/earthatnight.mov
http://sdcd.gsfc.nasa.gov/ESS/images2/transcript.html

It is interesting to note that 2-D and 3-D representations are selected for different visual portrayals. Earnshaw and Wiseman (1992) denote the following examples:

2-D--Used for maps
2-D with time sequence steps--meteorology, visualization of ice streams
3-D--Remote sensing (single scalar value associated with each position in a 3-D space)
3-D--Medical science, drug design, biochemistry, physical chemistry, archeological data analysis and reconstruction
3-D with time steps series--oceanography, computational fluid dynamics

Visualization of 2-D and 3-D data may be enhanced by recording from computer onto a videotape to allow for fast playback of large numbers of images.

In every case an effort is made to depict what is real in a 3-D world onto a screen which is 2-D. In scientific visualizations special modifications must be made to ensure accurate interpretation and presentation of scientific data sets. By viewing multidimensional data in easily understood forms or images on a 2-D screen, one can gain valuable insights into 3-D and higher-dimensional data sets that is otherwise impossible.

To add excitement to our visual world, we are now able to see “real time data” coming from satellites to supercomputers in very short time periods. Additionally with the advent of “virtual reality” we can actually not only view a 3-D rotating Earth, we can also zoom in and out of a location and “interact” with the objects. One practical use of this technology was the development of an air traffic control type simulator which provides “virtual practice” for air traffic controllers. The possibilities are endless for practical applications for this type of visualizations.

It must be remembered that perception is a process of taking in and understanding non-sensed object characteristics form one’s available sensory data. Brodlie, Carpenter, and Earnshaw (1992) noted that “we not only believe what we see: to some extent we see what we believe” (p. 75). We are assisted in perception by: context (added information around the object); perspective, lighting and shading; stereo views (give depth cues); and, movement (animation), i.e., watching a continuous event.

Our visual world is all of those things...3-D, colorful, filled with motion, and “real time.” How exciting it is that scientific visualization can almost recreate the real world right before our very eyes, but in a format where we can uncover the mysteries and interactive intricacies of our world. We have spoken little of the use of scientific visualization to observe and record the universe beyond Earth. Certainly this is important and exciting as we behold the surface of Mars, fly by and collect data from the other planets, examine Sun’s behavior, and send scientific instruments beyond our galaxy. In all of these scientific ventures, visualization will be key to understanding our visible universe.

The clients who use visualization are very diverse. In its entertainment application anyone who has viewed high tech, science fiction movies such as the 1999 Star Wars has visualization techniques to thank. Additionally, folks who enjoy interactive computer video games can appreciate the wonders of visualization.

One very important use for visualization is in medical techniques. Computers have enabled us to see inside the human body and to translate that information into insights that facilitate diagnosis, prognosis, and treatment of numerous human diseases and disorders. Some of these techniques include: MRI (magnetic resonance imaging); CT (computerized tomography) scans ; sonograms; and, PET (positron emission tomography). Each of these methods displays a specific volume portion or “slice” of the body and is therefore able to diagnose problems in a very specific area. Another visualization technology, MPR (multiplanar reconstruction) allows physicians to examine 3 D relationships that exist among various combinations of planar slices viewed with the scans mentioned above. Particularly with orthopedic treatment it is helpful to use MPR techniques to know exactly where to place needed plates, screws, etc. in repairing broken bones.

Another important use of visualization is in the treatment of patients with cancer. In oncology diagnosis and treatment tumors are treated with surgery to remove them, or with radiation therapy or chemotherapy to shrink and hopefully kill them. In each of these cases it is very important to see exactly how large the tumor is and where it is located. The goal in this treatment is to eradicate the cancerous tissue while keeping the surrounding healthy tissues alive and well. Great strides have been achieved in oncology diagnosis and treatment as a result of improved visualization technology.

Many additional applications exist for medical/surgical intervention, including brain surgery (neurological imaging), plastic surgery, and numerous others. Medical science has helped pave the way for advancement in visualization.

Visualization techniques have opened new doors for all scientists, but perhaps one of the most amazing applications has been for scientists in the Earth and Space sciences. While once our view of planet Earth was limited to pictures out of an airplane window, we now have spectacular images of our Earth from the moon and from “outer space.” Satellites viewing the Earth from beyond the Earth’s own atmosphere gather data via a variety of instruments and relay that data down to Earth where it is collected by supercomputers. The data can then be translated by scientists using computer programs, mathematical corrections, algorithms, etc. and can be presented via visualization techniques in many different forms. Some of this data serves as input for supercomputers which generate models of weather and climates. The final customer in this equation is the public who expect to see hurricane news accompanied by a swirling “Doppler radar image” which now many folks can understand in some way. In these days when “ozone” is a term understood by school children and adults, the images of the “ozone hole” (which we know is not really a hole) via satellite images makes that phenomenon more realistic and understandable. One further example is the El Niño/La Niña oceanic phenomenon and accompanying weather patterns unknown to most people prior to this latest El Niño, but by now a popular term often blamed for our current droughts or floods. The visual images shared by NASA, meteorologists, and others have greatly elucidated the meaning and effects of El Niño. Our public is becoming much more “science aware,” and visualization has greatly contributed to that awareness. Scientists can further use that data to predict future events and help the public to be proactive in preventing crises. For example, if it is known that an El Niño will bring poor fishing on the west coast of South America, it might be prudent for some people to change their mode of income generation to agriculture since rain will be more plentiful in that year. Likewise, roofers in California encouraged folks to repair their roofs before the onset of the rains from El Niño. Roofing business boomed and folks prevented damage to their homes when the sustained.torrential rains came. Conversely in countries which experience drought during this time period it might be prudent to grow cotton rather than rice for one or two seasons. It is estimated that El Niño caused approximately $33,000,000,000 of damage on Earth. By examining visual images over sustained time periods scientists can contribute to improved quality of human life and can help to decrease societal costs from loss.

Consider the following list of applications of scientific visualization using satellite data noted by Claire Parkinson, a NASA climatologist at Goddard Space Flight Center. Currently we obtain information about: atmospheric ozone; sea ice; continental snow cover; sea surface temperature; land vegetation; volcanic emissions; solar radiation reaching Earth’s outer atmosphere; atmospheric and land surface temperatures; wind speed; aerosols; water vapor; clouds; lightning; ozone; ocean and land topography; ocean circulation; ocean biological productivity; ocean evaporation; ice sheets of Greenland and Antarctica; the world’s mountain glaciers and ice caps. Using this information scientists can provide weather forecasts and major hurricane and storm warnings, identify and strive to correct critical changes in Earth’s landscape, identify global forest fires, oil well fires, oil spills, and monitor anomalies such as El Niño and global warming.

Visualization and science visualization have greatly improved our lives..and it has only just begun. The future holds great promise for understanding our “visual” world.

There are many stages and people associated with the visualization process. Basically there are instruments which collect data and/or people who enter data. All of this data must enter the computer...i.e. there is computer “input.” Once the data is in the computer it experiences “throughput” where the computer makes meaning out of the binary code (e.g. 11000100110000010000 etc.) that it receives. Computer scientists have written programs to help the computer interpret data in specific ways. The data is then in a form where it appears as “output” to the person at the keyboard. This simplistic explanation helps to see the relationship:



To illustrate this process consider the example of the NASA SeaWiFs project. For a complete explanation of this extensive International venture visit the web site/ noted here. (http://SeaWiFs.gsfc.nasa.gov/SEAWIFS/BACKGROUND/
SEAWIFS_BACKGROUND.html). Also of interest is a teacher site with lessons about “The Living Ocean.” SeaWiFs primary concern (http://athena.wednet.edu/curric/oceans/ocolor/index.html).

This project is part of NASA’s Earth Science Enterprise which collaborates with international private and public agencies to monitor the “health” of the Earth via data from satellites and other instruments. SeaWiFs satellite data provides Global Area Coverage (GAC) at 4 km of resolution every two days. Local area coverage data is provided at 1 km resolution. The data is recorded on board and then transmitted to a NASA facility’s antenna for downloading and processing via computers. The Distributed Active Archive Center at NASA’s Goddard Space Flight Center archives and distributes that data to approved users. It is interesting to note that NASA has a contract to purchase Earth-science research data from a private company, Orbital Sciences Corporation The public often harbors the misconception that all manufactured objects in space were built by, paid for, launched, and maintained by NASA. In reality these human-made space objects are built by private and public firms and funds world-wide. There are many attempts now to coordinate international private and public efforts to avoid duplication, reduce cost, increase efficiency, and provide an international network of information and research that can benefit all humans and the environment.

Once this satellite data has been captured by ground stations, the data must be interpreted via supercomputers and then output in a manner in which it can be understood and used. The schematic which follows on the next page provides a look at this process from satellite capture to user of the information.

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Data---Information---Insight Schematic

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What Happens at Each Level of Data Interpretation?

Using SeaWiFs as an example, the following is a description of what is occurring with data at the various levels presented in the schematic.

Level 0 --Raw data has entered the NASA computers from the satellite via the ground station’s antenna. At this point the level is being downloaded from the satellite and appears as all ones and zeros in code form. This is the first level scientists can access but they cannot really use the information yet. The data comes in one file per downstream.

Level 1 --This processed number code yields black and white pictures depicting brightness and radiance. There is a computer program which breaks level zero files into individual GAC (Global Area Coverage) files (4 km resolution) and LAC (Local Area Coverage) files (1km resolution) in orbital swaths. At this level, combining three of the SeaWiFs bands (1, 5, and 6) gives true color images. Data has been processed to show precise latitude and longitude of each pixel. Level 1A “image data” is in counts and Level 1B image data is in brightness units. Using brightness and radiance units to do time corrections allows for vicarious calibration changes at 1B.

Between levels 1 and 2 the data will be calibrated to ensure scientific accuracy.

Level 2 --At this level data has been calibrated via several mechanisms. On a monthly basis data is calibrated with lunar files (since the moon is a stable light source with a very regular phase pattern) to see if instruments are changing with time. In SeaWiFs, two bands are changing most in the near-Infrared range (Band 7 approximately 2.5% change and Band 8 approximately 7.5% change). These changes can then be compensated for mathematically to maintain data accuracy and integrity. Additionally sun detector and solar calibration tests are done daily. One further important calibration test is done via water buoys at Lanai, Hawaii. These buoys are changed every three months (1 in the water and 2 on the land) and measure the light field or “water-leaving radiance.” The satellite flies over the same locations and gathers the same types of data which can then be compared with the buoy data. In the 100 days of measurement thus far, there has been an exact match between satellite and buoy data. The water-leaving radiance data is used to make atmospheric corrections (errors do not generally exceed 5%). Level 2 data provides chlorophyll information and water- leaving radiance information. This level of data deals with small, specific places over a short period of time.

Level 3 --After leaving Level 2, data can be”time binned,” taking all 14 space bin files for one day and averaging them to make a one day file. Information can then be selected on a daily, 8-day (due to the way the orbit works--every 16 days going over the same orbit), monthly, seasonal, or yearly basis. In Level 3 data global modeling (e.g. climate modeling) is possible.

Level 3 data is generally what the public sees in newscasts. This data has been “rendered” by scientists and visualization experts to be more understandable by adding grids (e.g., latitude/longitude lines), overlays of color to denote boundaries (e.g., continent outlines in yellow on a black and white GOES image), or made into a model or an animated simulation All of this is made possible by modern visualization workstations with large amounts of memory and disk and with very powerful graphics capabilities in terms of available color range, resolution, and display speed. These workstations, like those at NASA, supply substantial computation power with very high-speed 3-D graphics. Particularly in areas of modeling, simulation, and animation and for real-time dynamical simulations, processing and display of copious amounts of data are needed. In some instances the only way scientists can analyze the validity or performance of the model is by visualizing it.

Another use of Level 3 data by scientists comes when there is a particular set of variables to be considered. One NASA scientist who examines sea ice noted that she uses level 3 data by shading the land (black or gray)over Antarctica or the Arctic, she is able to more accurately measure the surface area of the sea ice surrounding the continents.

It is exciting to envision the many improvements in visualization techniques that are on the horizon. Folks who have enjoyed interactive video games or games on the internet where they can interact during game plays with people from many countries can look forward to the world of virtual reality. Once again our human condition wants to “see” the world and even “imagined” worlds as they “really” are. We much prefer to see a movie in an IMAX format in front of a huge screen while feeling that we are “in” the scene and “feeling” the motion of the moment, than to see the same movie in front of our television set. Perhaps one day this will seem less thrilling when we all have HDTV (High definition television) which is already use by television networks for the excellent resolution and clarity it affords We are also thrilled by the 3D Disney World movie presentations which depict spiders dangling right in front of our noses or a meteor crashing toward us at warp speed only to seemingly stop short just millimeters from our faces via our 3D glasses. Our visual world is truly expanding. We prefer DVD movies over VHS formats because they are more realistic and “clear.” Folks sit in video arcades interacting with simulated speed car races, pretending to be that winner of the Grand Prix.

Scientific visualization also looms on the horizon of greatness. As computer capabilities greatly increase and workstations such as those used by the NASA SVS lab (Scientific Visualization Studio) become even more capable of handling vast amounts of data and graphics, the possibilities are limitless. Even now these facilities have the ability to show us a huge rotating Earth on a screen Geophysical features are actually from satellite data...so they are “real” and not simply and artist’s rendering based on photographs or data. We can then choose a place on planet
Earth and can zoom in on that place, even close enough to see and identify the very NASA building in which we are viewing this incredible Earth. How much closer can we be to real?

In the field of medicine will we be able to “visualize” tumors precisely as they appear in the human body with even better clarity and certainty than exists today?

Will the importance of human knowledge, skills, and intuition become less important as scientific visualization tools make diagnoses more exact and less interpretive? Giger and Pelizzari note in their Scientific American article on “Advances in Tumor Imaging” (98) that “The display technique employs scientific visualization methods similar to those used in the geosciences or astronomy to fuse information from several imaging tools into a single coherent picture....As a result, computers can complement the radiologist’s eye. And the availability of high-quality digitizers and fast computers makes it possible to process medical images in minutes. ...An intelligent workstation would serve as a second reader (like a spell-checker for computerized texts), leaving the final decision regarding the likelihood of the presence of cancer to the radiologist.” (pp. 82-84). It is obvious that humans not only design the input that goes into the computers, humans also “use” the output to make decisions based on knowledge. While robotics and virtual reality seem to be able to simulate what humans do, they will never replace the incredible capabilities of the human brain.

We end as we began...with a visualization. As you read the following story, think about the images that you “see” in your mind’s eye.

Five blind men were on the way to the market. Each one in turn came upon an elephant. Never having come upon such an extraordinary beast before, they each wanted to see for themselves what an elephant was truly like.

Blind men must “see” with their hands, so each blind man approached the elephant, felt him cautiously, and then proceeded on to the market. Later when the five blind men met in the market, they began bickering among themselves. Each had seen the elephant, but none could agree upon what they had seen.

The first said that an elephant is like a great tree with a leathery bark.
The second insisted that an elephant was more like a length of rope.
The third said, “An elephant is like a huge leaf flapping in the wind.”
The fourth insisted it was like a great wall extending as far as he could reach.
And the fifth knew for certain it was like a huge snake.

This arguing went on for some time and seemed to be endless. No matter how long they argued, none could agree upon what they had seen. Each man had seen a different part of the elephant’s physical being.

The first blind man had stepped forward and wrapped his arms around the elephant’s leg and indeed felt a leathery tree trunk. The second blind man had grabbed the elephant’s tail & likened it to a length of rope. As the third blind man approached the elephant, he had felt the elephant’s huge ear brush across his body and thought it was like a large leaf blowing in the wind. The fourth blind man had run smack into the elephant’s side and as far as he could reach, all he could feel was as a wall blocking his path. The fifth blind man had reached out for the elephant and found his trunk - moving and squirming like a snake hanging from a tree.

Indeed it would appear that having a complete picture of the elephant in one’s head would provide a better slice of reality into what elephants really look like. In visualization and scientific visualization we are assisted in seeing the whole picture. One NASA scientist described the role of scientific visualization as helping us to “understand what we need to know better and to understand what we don't yet know at all.” He noted that “without visualization techniques it is impossible to figure out what is going on with those huge available data sets.”

This story also illustrates the way many satellites collect data. A typical satellite has several instruments that measure different properties of physical phenomena. For example, a spacecraft may collect images in many different wavelengths (infrared, visible, ultraviolet, to name a few). Another satellite may collect data to measure: surface features; abundance of minerals or phytoplankton; global shape, climate, rainfall; and, magnetic field and x-rays and gamma rays from an object. The integration of each of these snapshots produces a detailed picture of the object. Additionally these parameters can then be “overlaid” to produce information about a specific phenomenon or event such as El Niño.

Our visual universe continues to harbor many unknowns. It is the human condition to wonder and to explore...to seek answers, solve problems, and to see who it is that may be our neighbors in this vast universe. It is for these scientific explorations that visualization will provide the tools and keys to unlock the unknown and provide insight into our visual universe.

Brodlie, K.W., et. al., Scientific Visualization; Techniques and Applications,
Springer-Verlag, Pub., New York, 1992.

Earnshaw, Rae A. and Wiseman, Norman, An Introductory Guide to Scientific Visualization, Springer-Verlag, Pub., New York, 1992.

Giger, Maryellen, and Pelizzari, Charles. “Advances in Tumor Imaging,” Scientific American; Science’s Vision: The Mechanics of Sight; 1998.

Nielson, Gregory, Hagen, Hans, and Muller, Heinrich; Scientific Visualization: Overviews, Methodologies, and Techniques; IEEE Computer Society, Pub., Washington; 1997.

Parkinson, Claire, Earth from Above, University Science Books, Sausalito, California; 1997.

Thalmann, Daniel; Scientific Visualization and Graphics Simulation, John Wiley and Sons, Pub., New York, 1990.

Authors: Lynn Birdsong, Greg Helms....GESSEP Program

Goddard Advisor: Jarrett Cohen....Space and Earth Sciences Division

Contributors: David Adamec, Yi Chao, Rick DeVore, Gene Eplee, Gene Feldman, Fritz Hasler, Dave Herring, Alex Kekesi, Peggy Li, Mike Manyin, Claire Parkinson, Marshall Sheppard, Greg Shirah

Maryland Core Learning Goals (Science Grades 6-8):
1.B.6
2.1 2.3 2.4 2.5
3.1 3.2 3.3
4.1 4.2 4.3
6.1 6.2 6.3


Maryland Core Learning Goals (Science Grades 9-12):
1.4
1.7
2.1.1
2.1.2
2.3.3
2.7.3
3.5
4.3
4.6
5.7


National Geography Standards
1.
2.
3.
4.
5.
7.
8.


National Content Standards for Science Education, Grades 5-8
A.1 A.3 A.4 A.6 A.7
B.3
D.1 D.3
E.1 E.2
F.2 F.3 F.4 F.5
G.1
G.2
G.3


National Content Standards for Science Education, Grades 9-12
A.3 A.4 A.5
B.6
C.5
E.2
F.3 F.5 F.6
G.2


NCTM Curriculum Standards, Grades 5-8
2.1 2.2 2.4 2.5 2.6
3.1 3.2 3.4 3.5
4.1 4.2 4.4 4.5
8.1 8.2 8.3 8.4
10.1 10.2 10.3 10.4 10.5
12.6


NCTM Curriculum Standards, Grades 9-12
1.3 1.4
6.1
11.2


Technology Foundation Standards for Students
1.b
2.c
3.a
5.a
6.a 6.b