Graphing and Visualizing Multiple Variables

CS137 Assignment #5

 

 

1. Dates

Out

Thurs, 10/7

Due

Tues, 10/12

 

2. Goals

  1. Gain an understanding of the sources of experimental and computational data.

  2. Learn about scientific data and identify relationships among variables in scientific data.

  3. Learn to create a visualization icon showing variations in the relationships within variables in a dataset.

  4. Learn how well visualizations created with your icon might translate into a 3D Cave setting.

3. Readings

 

            Check the website for updated reading information.

4. Assignment

This assignment should be completed in groups. For this assignment the groups will be:

Group1: Claudia, Gabe
Group2: Helen, Joseph
Group3: Jane, Edwin
Group4: Julie, Alex
Group5: Janet, Sascha
Group6: Laura, Ming-Ming , Misha

 

The 2D flow handout we discussed in class contains 2D flow data around a cylinder -- you can think of it as a river flowing around a bridge pier with a circular cross section.  The data is calculated with using computational fluid dynamics (CFD) simulations, much the same way the artery or bat flow cases are.  Because this data is 2D, it is a simplified version of the data that we use in the Cave bat visualization.  The lessons we learn in this exercise will apply directly to visualizing flow quantities on bat wings.  Because this is where the flow interacts with the bat, the data is some of the most important, scientifically. It is easier to work with 2D data like this than the full 3D dataset because we have essentially a 2D visualization problem.   The handout shows a number of different quantities all over the same space.  If they were on acetate, you could overlay all of them to see how the different values relate.

 

Part 1: Key/Legend Design

Create keys or legends for all of the data values.  For each one, it should be clear what values correspond to what visual representation.  Label the axes of the keys with numeric data values.  You’ll need to make up the numbers.  In general, zero will be clear.  Make your own choice about non-zero values and try to also fill in the units (e.g. meters/second for velocity).

 

Part 2: Icon Design Showing Multiple Variables

Use your understanding of the data in the 2D flow handout (from Siggraph course) to design a visualization icon for the six listed variables of the flow that clearly shows the values evident in the data. Each visual variable (length, shape, color, pattern etc.) should correspond to one data variable, the visual variation tied closely and legibly to the variation you see in a given aspect of the data (e.g. longer icon means faster flow, redder icon means greater pressure).

Try to pack as many visual variables representing aspects of the flow as you can into a single icon. You can also use how icons relate to one another to encode data values.  The various visual variables must be simultaneously legible and not confuse the reading of any other variable in the icon. When you can’t fit any more, start a 2nd icon, with a different set of characteristics from the first, to show the remaining variables. You should execute a sufficient number of permutations of each icon to encompass the range of fluctuation of the variables in the data.  When designing your icon, place a priority on immediate legibility and clarity of the relationship between the variables. 

 

Once you have determined a suitable icon, create a visualization of the cylinder data by populating a 2D picture with several variations of your icon(s) that represent, as closely as you can, the fluctuations that you see in the handout.  Essentially, you are designing a new icon-based visualization of the same data that you have in there, but packing all the information in these icons. Any material may be used (traditional materials, 2D computer graphics materials, etc.) to create the 2D image, as long as it can eventually make its way into digital form, via scanning, etc., so that we can look at it in the Cave.

 

Make a legend for us that shows how a change in each variable affects the size, shape, color, etc. of your icon(s). 

 

Scan these at the Cave and import them into your CavePainting application (you’ll get the program. See the Resources section).

 

Create 4 rectangles with that image on them. Resize them so that you have 1 rectangle of each of the following sizes: 6 in, 1 ft, 4 ft, 8 ft.

 

You can also replicate your icons by painting them in 3D using CavePainting. Import any textures you might need to do that.

 

Arrange these around the Cave and save to a file for viewing during class.

   

5.     Resources

5.1 Getting the support code for the assignment.

Go to your cs137/ directory and type “cs137handout   5”. This will get the support code into your account in a folder called 'asgn5'. It’s the same you had for assignments 2 and 4, so you should be familiar with these files.

Scan your images and put them into this directory, update the settings file with their names and run (./run  cave) the application to create your squares.

Save your work.

 5.2 Handing in your assignment.

At this point you have a painting saved in your directory (one of the .ff3d files) with your icons in it. Edit the 'settings-asgn5.cfg' file again and change the line to load a file to reflect the name of your final cavepainting:


LoadArtwork nameofyourff3dfile.ff3d

Run the program to make sure it loads the file you want before handing in. Finally, to hand in your code type:

cs137handin5   groupname

Where 'groupname' is a name that you assign your group. Go to the kiosk. On the CS137 folder, there should be a button named 'asgn5.groupname'. Press it and make sure it runs on the cave and loads the right painting.

6. Questions

  1. How well are data values discernible in your iconic visualization?

  2. How well are relationships among data values visualized easily by your icon design?

  3. What are the factors behind your choice of visual characteristics of the icon(s)?

  4. How did your 2D design work as you expected within the Cave?  What was unexpected?

  5. What are additional factors that need to be considered when designing visualization for the bat wing data that are different when you think about this problem in 3D in the Cave as opposed to in 2D on paper?

 

7. Checklist

 

o     Created and labeled six legends for the data values in the handout

o     Created a second legend for each of the data variables showing how your icon change correlates with the data value change.  Use the same range of values for the legend as you used for the handout legend.

o     Created a 2D image in digital form or scanned into digital form that has been populated with your icons.

o     Translated all this into the Cave and saved a painting from there.

o     Tested re-loading the painting in the Cave from the kiosk.

o     Hand in

o     Answered assignment questions and e-mailed to TA.