This pseudo visualization demonstrates the foundational marks and channels needed to map global tree cover change, using a parabola to show how GPS-derived x and y coordinates will position data. A series of circles, distributed via d3’s `selectAll` and `join`, are placed using computed `cx` and `cy` attributes, while their fill colors apply `interpolateRdYlGn` to encode values from 0 to 2500. The example uses d3 v7 APIs, including `symbol` and `symbolsFill` for alternate shapes, and renders directly into an SVG canvas sized to the browser window.