CS490 VIZ - Fall 2020
Programming Assignment 4: Trees

Key Dates

Handed out: Monday, October 12, 2020
Due date: Monday, October 26, 2020 (before 11:59:59.99 PM)

Objectives

In this fourth assignment, you will apply three visualization techniques to the visualization of a tree dataset corresponding to the class hierarchy of visualization software named flare. The goal is to allow you to experiment with different existing solutions for the representation of trees and to analyze their respective benefits and limitations in the context of a fairly large dataset. An important aspect of the work here is the creation of the requested tree layouts. While various python libraries offer some tree layout capabilities, they are usually limited and buried in the internal data structure used by the plotting functionalities of the library. With that said, you can either use existing layout solutions available in python (with the caveats mentioned previously) or implement your own.

Tasks

You first task consists in creating a node-link visualization of the dataset. Since the various nodes of the tree are provided with a numerical value, you will apply a color coding to the circle associated with each node to represent this value. In addition, your visualization should display the name of the class next to this circle. You will include a slider in your visualization to control the maximal depth of the tree displayed. That means that all the nodes located at that depth will hide their subtree (if any). Finally, you will include a push button that allows the user to toggle between a horizontal and a radial layout for the node-link representation.


Deliverable: p4_nodelink.py

Task 2: Layered Diagrams

For the second task, you will replicate the features of the visualization created in Task 1 but this time use a layered diagram layout. As in the previous case, you will include a slider to control the default maximum depth. Also, you will allow the user to switch between a horizontal layered layout and a radial layered layout.


Deliverable: p4_layered.py

Task 3: Enclosure Diagrams

The third task consists in creating enclosure diagrams to visualize the dataset. Specifically, I am asking you to create a Treemap representation of the file structure. You are free to choose the color mapping of your choice in this case. In contrast to prior tasks, your visualization will not offer the collapse/expand feature, nor will it offer a radial layout. It should, however, include a slider to control the maximum tree depth shown in your tree map.


Deliverable: p4_enclosure.py

Task 4: Discussion

Your final task in this project will be to discuss the respective merits and limitations of the various visualization techniques considered in this project. Did you find one of the techniques to be superior to the others? If so, why? In addition, are there specific aspects of each method that you find beneficial? Justify your answer.


Your discussion should not exceed a paragraph or two.

Data Set

The dataset is available in JSON format here.

Submission

Submit your solution for this project on Brightspace before October 26, 2020 at 11:59:59 pm. Refer to the instructions below.