From CS 294-10 Visualization Sp10
A rationale for my visualization:
The data in this case encodes the amounts donated by each country, as well as the amount donated per person, into a single, effective visualization. The total amount, which I felt was the most important variable in this case, is prominently encoded in the height of the bar. I found that this was a straightforward method by which users could visualize the total amounts donated by each country. Initially, I did this with a uniform linear scale, however as a result, I found that all countries that donated under 10 million had extremely small bars that could not be compared. To remedy this, I switched to a log scale. Although this made it more difficult to find the exact differences in the total amount donated between two countries, it made it much easier to make relative comparisons across nations, even companies that had donated smaller amounts.
I found that not only was the total donation by each country interesting, but also the amount donated by each person, as this provided somewhat of a quantitative measure of generosity. To effectively encode both variables, my initial thought was to vary the width of the bar graph. However, due to the interference caused by a distortion of the aspect ratio, I decided that this would be misleading. As a result, I used luminance instead. A darker color represents a more generous donation (larger amount per person). While this does not provide as accurate an encoding as bar height, I found that this was a less important variable for direct comparison, and more important in the sense that very generous nation such as Canada and Sweden were made directly apparent, while countries that had not donated very much were shown in white.
Finally, to differentiate organizations from countries, I drew the bars for organizations with a dotted line. This way, readers would be less tempted to form direct comparisons between countries and organizations.