HW2 Theory: Tasks and Validation


The purpose of this assignment is to provide you with some experience describing the tasks of an existing visualization tool and potential methods for validating that tool. You will also gain some familiarity using Processing to import a dataset and create a simple visualization. This assignment must be completed on your own. Each part is equally weighted: please follow the submission guidelines on T-Square to get full credit.


Part 1: Written Report (1-2 pages)

Below is a link to a movie that describes a visualization tool called "Dust and Magnets." Watch the movie and write a report explaining what the capabilities of the visualization tool are, what tasks it supports, and how it could be validated. Your goal here is to perform an abstract analysis of a visualization tool using the approaches described in the text and in class.

Your report should consist of three sections on one or two pages. First, describe what the general visualization idiom of the tool is. What is the chosen representation for the data, and what form does interaction take within the visualization? You don't need to jump ahead to sections we haven't covered, just try and tell us what the tool does. Second, write one section about the tasks that the tool supports. What abstract tasks, expressed as action -> target pairs, does the tool facilitate? There should be several. Think back to the insights you recorded for the last assignment. Could any of your questions be answered by the tool? How do these questions relate to the supported abstract tasks? Third, discuss potential methods for determining if this is an effective tool. What level(s) of validation do the designers appear to be targeting? What threats to validity exist, and what are some potential approaches to addressing those threats? Why wouldn't other potential approaches be suitable?

Grading: We will evaluate the quality of your analysis of the visualization tool within each section. We will evaluate if you followed the directions and estimate the quality of your conclusions. We will evaluate how well you justify your conclusions based upon the material we've covered in class so far. Please proofread your submission before submitting it and make sure it is free of spelling and grammar issues.

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Part 2: Software

You are going to write a sketch capable of visually representing text data. The data consists of a list of 1-grams, or words, and how frequently they have occurred in Google Books. This is a much larger data set than you used in the previous assignment, but still only contains a subset of the potential words in the English language. You are going to write a sketch that generates a timeline of the relative change in word frequency over time, similar to the chart in the image below. This will be somewhat similar to NameVoyager, however, you will not be creating a stacked area chart. Just timelines for the selected words.

Your system must support the following capabilities:

Most of the information required for this assignment can be found in the Processing reference. The interactive components (e.g., buttons, dropdown menus, sliders) will be made much easier if you employ an existing library such as controlP5, though you cannot use such a library to render your chart. Please provide all of your code in a single sketch directory named "nGramVis" that you submit. This directory must include a file named "nGramVis.pde" with setup() and draw() functions so that we can run it.

Grading: Your assignment will be graded on whether it can perform the list of functions correctly. Each capability will be worth one fifth of the grade for this part of the homework. The extra credit mentioned in the descriptions are each worth one tenth of the of the grade for this part of the homework (half the value of getting the primary functionality correct). Feel free to attempt any, or all, of the extra credits but please target the primary functionality first. Please use good naming conventions and appropriate comments to help us read your code.

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Dust and Magnet

Dust and Magnets Downloadable File [mov]

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Data Set

Google Ngrams 1-gram Reduced Set [zip]

The zip file contains four files in comma-separated-value format:

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