Equal-Area to Mercator: Zoom-Dependent Interactive Maps

Why are you even reading this blog if you’re not into map projections and the mathematics behind them?

Ben Joffe has you covered with an approach to creating multi-projection interactive maps that morph between equal-area and Mercator-style conformal projections based on the zoom level. We’ve had these flexible map projections for a while—MapboxGL introduced one as a commercial solution in 2022—but Joffe uses a simpler formula that includes constants derived from subjective visual tuning.