Due Wednesday, November 15th, 12 Noon

CS 4460 - Information Visualization - Fall 2017

Programming Assignment 4: Brushing and Linking


In this assignment you will create a version of the charts from Nadieh Bremer's Urbanization in East Asia narrative visualization. We highly recommend going through this visualization as a great example of storytelling and to learn more about the dataset.

In this assignment you will create multiple coordinated charts. You will create 6 total subplots. Your submission should include a bar chart and a dot histogram for each of the following urbanization measures:

The bar charts should compare the 2000 and 2010 metrics for each country. While the histograms should show the distribution of the percent growth for each city (Note: percent growth is already calculated for all three metrics). Your final chart will look like this:

Lab Result

Your subplots will also need to support coordinated interactions for brushing and linking. First, your dot histogram charts will have brushing in the x-direction. The brush will highlight the selected cities from that histogram in the other 2 histograms. Note that only one brush can be active at a time, so you will have to save the state of the active brush. The interaction should look like this:

Lab Result

Next, your submission should include linking from the bar charts to the histogram plots. Since the bar charts display all of the East Asian countries, you will use mouseover and mouseout events (aka hovering) to trigger a linked highlighting in all other views. The dots in the histogram should be highlighted if they are the same country, and the grouped bars of that country in the other 2 bar charts should be highlighted as well. The interaction should look like this:

Lab Result

You will use the dataset at ./data/asia_urbanization.csv to re-create the Urbanization in East Asia interactive visualization. Use the above relative path when calling d3.csv(). We will deduct 2 points if you do not use a proper relative path.

Here is a snippet of the dataset:

city country latitude longitude land_2000 land_2010 land_growth pop_2000 pop_2010 pop_growth density_2000 density_2010 density_growth type_country
Tokyo Japan 35.7090259 139.7319925 5434 5570 0.025 27695526 31788261 0.148 5097 5707 0.12 high-income
Jakarta Indonesia -6.2087634 106.845599 1338 1600 0.196 16291976 23431674 0.438 12174 14643 0.203 lower-middle-income
Beijing China 39.904211 116.407395 1827 2716 0.487 10754014 16707094 0.554 5887 6151 0.045 upper-middle-income
Seoul Republic of Korea 37.566535 126.9779692 1067 1192 0.117 14277211 15898238 0.114 13378 13342 -0.003 high-income
Bangkok Thailand 13.7563309 100.5017651 1910 2126 0.113 7825880 9555372 0.221 4098 4495 0.097 upper-middle-income

You will use this dataset to create the above multiple coordinated plots.


The data-bindings on the grouped bar charts are:

The data-bindings on the dot histograms are:

You will need to re-configure the dataset two different ways:

  1. For the grouped bar charts, you will want to use d3.nest() to compute an aggregated dataset for each country. You will compute the sum for land and population, and the mean for density.
  2. For the dot histogram you will need to use d3.histogram to compute a binned dataset based on each measure: land_growth, pop_growth, density_growth. As mentioned above to get good binning use xScale.ticks(80) to compute the histogram's thresholds() like they do in this example. Where xScale is a scaleLinear function that maps the input domain of the growth measure to the width of the histogram.

You will create this interactive chart using D3's Brush tool. We will cover how to create brushing in Lab 8, so stay tuned. In the mean time, take a look at these examples for how to add brushing:

Reminder that this is an individual assignment. The code you turn in should be your own creation. You are certainly welcome to seek assistance from the TAs as you work on the assignment, however.

Starter code

All of the starter code for the Programming Assignments can be found at the HW Github Repository. git clone this repository for this assignments starter code. You will need to git pull for all future starter code.

You are required to use the starter code for all programming assignments.

What to turn in

You will submit your code via T-Square. Compress your code (the 04_brush_and_link directory) into a zip file. Upload and submit this zip file via T-Square.


Your zipped code should be submitted to T-Square by 12 Noon on Wednesday, November 15th


This assignment will be graded out of a 100 point scale. If your D3 code does all of the following you will receive all 100 points:

  1. Creates 6 total subplots. 1 grouped bar chart, and 1 dot histogram for each of the 3 urbanization measures. All charts follow the data-bindings in the above "Data-Bindings " section.
  2. The dot histogram subplots support x-direction brushing between plots. Only one brush can be active at a time.
  3. The grouped bar charts support "on-hover" linking to all other charts. When hovering over a group of 2 bars, the same country will be highlighted on the other 2 bar charts and all cities from that country will be highlighted on the dot histograms.
  4. The entire visualization is contained within one SVG element.
  5. You are required to add a title, labels, legends, and axes to all charts.

You will not lose points on any of the following:

  1. The styling of the chart, grids, axes, legends or labels
  2. The number of ticks in the axes
  3. The number of bins used in the histogram, but all dots should still be legible
  4. The number of bins used in the color scales
  5. Conventions or legibility of your code
  6. Handling any other datasets than ./data/asia_urbanization.csv

Extra Credit

We will be giving up to 10 points of extra credit for styling your charts. Or any useful feature that enhances your visualization. Please make note of the additions/embellishments in the notes of your T-Square submission.