A scatter plot displays global cities by population on the x-axis and GDP in billion USD on the y-axis, with each city’s points colored via a categorical scale using `d3.scaleOrdinal` and a combined `schemeCategory10` and `schemeSet3` palette. The visualization loads a CSV from a GitHub raw URL using `d3.csv`, parses numeric fields, and renders circles with `d3.selectAll('circle')` and `.enter()`. Axes are generated with `d3.axisBottom` and `d3.axisLeft`, formatted using `d3.format('.2s')`, and a legend lists city names with matching color swatches. The SVG output uses D3 v6 with a light-gray background and Arial font.