Geographic projection affects the accuracy of visualizations

Due to the usage of Mercator projection, at higher latitudes, the points are less dense, and the color can be different even if the actual density of points is the same.

No files or tests are named. Start by locating where the visualization selects or applies the Mercator projection, then reproduce the reported density and color difference at higher latitudes. Done means equal point densities produce comparable visual results across latitudes, with relevant visualization tests or manual checks passing.

Written by the indexing model from the issue text.