This is a gorgeous radar chart designed by Nadieh Bremer. So far I am doing well on integrating it with my World Economic Freedom Index dataset, although some further changes are still necessary for better interpreting. You can see from the chart that the data indicates that the economic of the United States is generally more free than the economic of China, except for the two aspects, Fiscal Health and Government spending.
Here're my findings and future improvement ideas:

• The radar chart is flexible with the number of axis. It is not fixed, so you can have as many axises as you like. Here I have 12 indexes describing the economic freedom. Hence, my radar chart is a 12-axis chart.
• The function of the scale need to be changed according to need. The 'default' function is about the percentage.
• The max value of the axis is not fixed too. It is depending on the data you entered in. Changes are needed if you want the fixed maximum value.
• It is so frustrating that the data entry is by typed not imported from csv or json. I think that for the future improvements I can use d3 to import formated data instead of typing.
• There's no tooltip by placing the mouse on the inner information, which means that you cannot tell whether the red is China or not unless checking the src. I think I can add a tooltip to the radar chart to make it better.