Google Maps made the world a square of tiles, and Web Mercator became the map standard

In 2005 Google Maps faced a rendering problem: a seamless, fast, zoomable world map over ordinary web connections. Its solution combined two choices that are now taken for granted — use a Mercator-style projection with a spherical formula, and cut the map off near ±85° latitude so the projected world is exactly square.

With a square world, tiling becomes trivial arithmetic: at zoom 0 the whole map is one 256×256-pixel tile; every zoom doubles both axes, so each tile address is a pair of integers and each zoom level quadruples resolution. Tiles can be pre-rendered, cached and fetched independently — the property that made panning and zooming feel instant. Google's own documentation still describes the 256×256 base tile and the ±85° cutoff "to make the resulting map shape square, which allows easier logic for tile selection."

The scheme spread by compatibility. The EPSG registry records the projection as "WGS 84 / Pseudo-Mercator" (EPSG:3857), scope "web mapping and visualisation," used by Google Maps, OpenStreetMap, Bing, ArcGIS and ESRI; Esri even moved ArcGIS Online onto the same Mercator-based tiling scheme in 2009 rather than fight it.

Square the world; tile it by powers of two

A square world makes every tile address simple integer math at any zoom.

256×256 power-of-two tiles are pre-renderable, cacheable and streamable.

Every rival adopted the same scheme, so one projection covers all web maps.

The spherical formula keeps local shapes and directions usable at street level.

Choose the projection that makes the engineering trivial: a square world with power-of-two tiles turns map streaming into integer math, and compatibility made it the standard.

Web Mercator (EPSG:3857) became the default projection of virtually every online map — Google Maps, OpenStreetMap, Mapbox, Bing, CARTO and Esri — and the Google-style tiling scheme is the baseline for raster and vector tile services. GIS tools still warn against using it for area calculations, but for display it won.