When most people hear the word “data,” their thoughts turn to numbers or text. Increasingly, however, the data we may wish to analyze includes images. Consider the following data, in which a dozen voters ranked the top 25 college football teams at the end of the 2014 season. Teams receive (26-k) points for each kth-place vote. That is, 25 points for each 1st-place vote, 24 points for each 2nd-place vote, etc., down to 1 point for a 25th-place vote. While voter, rank and points have been captured numerically, the college names are nowhere to be seen — only a logo is present.
Before JMP 12, in order to analyze data like this we would have had to create a new column, typing in each school’s name (and this assumes that we know each school’s icon, which we may not.) With the support for images within data tables in JMP 12, we can simply analyze the table in its present state.
Using the Summary platform, we cast the Icon column as a Group column, and request the statistics of interest.
Notice I’ve used another of the new features in JMP 12: the Histogram statistic, available at the bottom of the Summary platform's Statistics drop-down menu. This writes images of histograms (of the ranking values, in this case) to each row in the summary table.
Sorting the results in descending order of the Sum(Points) column produces the table below. Notice that the histograms give us a quick overview of the trends in the data, while the statistics provide supplementary detail.
Using the scroll bar to move quickly down the rows of the table, we can see the distributions move from left to right, and it is also easy to see the increased variability in the voters’ opinions of teams whose point totals fell in the middle of the distribution. No. 1 Ohio State exhibits no variability in its rankings, but Ole Miss' histogram indicates a considerable spread of opinion, as that school was ranked as highly as 11th by one voter, while another voter left it unranked (as the N Rows value is 11, but there were 12 voters.)
We can also use these images as labels in graphs. Below, I’ve plotted the maximum vs. minimum rankings using Fit Y by X, and I’ve drawn a line at Y = X. Since each point’s vertical distance from the line gives us the range of its rankings, it is easy to pick out the teams with the greatest difference between their maximum and minimum rankings. By turning on the Icon column’s Label property, and labeling all rows, we can hover over any point to see the icon associated with it.
While hovering, you’ll see an icon for a pin in the upper right corner. Click it to keep the information visible as you move elsewhere on the graph.
Once the icon is pinned, you can right-click on the icon to access other options, such as linking to the point with a tag line and inserting text.
As you can see, the support for images within data tables is a powerful feature in JMP 12. Next time, I’ll have more on using images within graphs, such as how to create images from analysis results to make a linked graph like the one below. See you then!