A scatterplot of seismic reflectivity data maps x/y sample positions, with each point colored by its P-wave slowness value. A 30-level density contour overlay, computed via `d3.contourDensity` and rendered as SVG paths with `d3.geoPath`, highlights clusters in the point distribution. The visualization uses `d3.scaleLinear` for axes, `d3.scaleSequential` with `interpolateReds` for color encoding, and `d3.axisBottom`/`axisLeft` for ticks. The background rectangle and circles are drawn with D3 joins.