9.10.10

Nobel Prizes and Tool-Tip Charts

Recently Tableau published a  how-to for placing bar charts on a map instead of the pie charts that are part of the selection for Marks.  I've never used the pie charts as I find them too busy, so I thought I'd try this brilliant solution provided by  Andy Cotgreave.  The full details are available on theDataStudio's blog.  Very easy to follow and very clever.



The trick is to put the information into a tool-tip using a similar formula for in-cell graphing that many have used in Excel (Andy gives credit to the same Excel MPVs that I've mentioned on the Clever Monkey's page).  To do this, you create 2 new calculated fields for each of the variables and display them inside the tool-tip.  One field to calculate the % and another to use the in-cell graphing formula.  Hover your cursor over a bubble on the map and the breakdown by prize type will be displayed.



The Nobel data was obtained from a BBC article Which Country has the best brains?  Nice of them to include an .xls spreadsheet with the results.  There's not a lot of data involved, but for this exercise - for me, less is more.  To learn more about the Nobel Prizes, check out their site http://nobelprize.org/.  There's some interesting detailed information on the Facts and Lists page.

The only difficulties I had with this exercise was in dealing with NULL values.  In Tableau Public, you handle NULL values in formatting, on the Pane tab, under Special Values.  I could not seem to get the numeric field to hide the value so I placed a "-" in the text field.  For the text variable, which produces the bars in the Tool-tip chart, I could not seem to find a way to have the field display anything other than NULL.  I'm sure there's a way to have nothing appear, but I haven't found it yet.

The formula that Andy provides includes 100 █ characters.  With this data it resulted in a messed up chart if a country only had one prize awarded, so rather than multiply each % calculation by 100, I used 10 to make fewer bars present in the Tool-tip. Not mathematically accurate, but I'm not presenting the % figures on the chart.

Well, that was fun. Thank-you Andy! Now if I could only figure out how to present median times in a bullet chart (I've been wrestling with this one for weeks).

No comments:

Post a Comment