Radar chart
A radar chart, also known as a spider chart, compares two data series across five categorical axes: Visualization, Machine Learning, Data Manipulation, Web Scrapping, and Search Engine. One series shows full values of 1, while the other displays fractional values. The SVG-based visualization, built with D3.js v3, uses a custom `RadarChart.draw` function to render circular level rings, percentage labels, axis lines, and filled, semi-transparent polygons for each series. The chart includes hover interactions and a color scale from `d3.scale.category10()`, with static legend titles defined in the accompanying script.