This visualization shows the spread of influenza across French regions for the year 2014, using a choropleth map where each region's color intensity corresponds to the weekly reported case count. A slider at the top allows the user to step through each week of the year, updating the map’s fill colors and displaying the specific week’s date. The map is rendered using D3.js (v3) with a conic conformal projection, and the color scale is defined by `d3.scale.quantize()`. The code loads geographic and CSV data asynchronously via the `queue()` and `defer` methods.