A basic scatterplot maps four pairs of numbers from the `xdata` and `ydata` arrays onto a two-dimensional chart. The visualization uses the D3 v2 library to create linear scales for both axes and draws circular points with a fixed radius and partial opacity. The chart renders axes via `d3.svg.axis()` and updates the points through `g.selectAll("scatter-dots")` in a `redraw()` function, though the code does not invoke this function, so only the axes and empty plotting area are visible on load.