This interactive visualization displays borehole depth and temperature measurements over time, plotted as red circles connected by a steelblue line. Users can switch the y-axis variable between Depth and Temp via dropdown menus, while the x-axis remains fixed to date. The chart uses D3 v5 scales, axes, and a line generator for rendering, with animated transitions on circle positions. SVG elements are updated through enter/merge/exit selections, and the menus are built using a reusable dropdownMenu module.