GeoMapSuite
Projections & Grids

Web Mercator (EPSG:3857 / Pseudo-Mercator)

Direct Definition: Web Mercator (EPSG:3857, formerly EPSG:900913) is the projected coordinate system used by virtually all commercial interactive web map tile providers (Google Maps, OpenStreetMap, MapLibre, Apple Maps).

Technical Details & Mathematical Formulation

It projects spherical WGS84 coordinates into a square 2D planar surface where north is always up and local angles are preserved (conformal). However, it exhibits extreme area distortion at high latitudes: Greenland appears as large as Africa, even though Africa is actually 14 times larger in land area.

Mathematical Formula:x = a \cdot \lambda,\quad y = a \cdot \ln\left(\tan\left(\frac{\pi}{4} + \frac{\phi}{2}\right)\right)
Interactive CalculatorMap Radius Tool

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Related Geodetic Concepts

Universal Transverse Mercator →Tissot Indicatrix →
Frequently Asked Questions

People Also Ask About Web Mercator (EPSG:3857 / Pseudo-Mercator)

Answers to key questions, technical definitions, and practical geodetic applications.

QWhat does the term "Web Mercator (EPSG:3857 / Pseudo-Mercator)" mean?

Web Mercator (EPSG:3857, formerly EPSG:900913) is the projected coordinate system used by virtually all commercial interactive web map tile providers (Google Maps, OpenStreetMap, MapLibre, Apple Maps).

QWhat is the mathematical or technical basis of Web Mercator (EPSG:3857 / Pseudo-Mercator)?

It projects spherical WGS84 coordinates into a square 2D planar surface where north is always up and local angles are preserved (conformal). However, it exhibits extreme area distortion at high latitudes: Greenland appears as large as Africa, even though Africa is actually 14 times larger in land area.

QHow do professionals use Web Mercator (EPSG:3857 / Pseudo-Mercator) in GIS and surveying?

Cartographers, geospatial software engineers, and navigators utilize Web Mercator (EPSG:3857 / Pseudo-Mercator) to guarantee mathematical precision and consistent spatial reference frames across global datasets.

QWhich category of geodesy does Web Mercator (EPSG:3857 / Pseudo-Mercator) belong to?

This concept is cataloged under the "Projections & Grids" domain in the GeoMap Suite cartographic knowledge index.

QCan I test or calculate Web Mercator (EPSG:3857 / Pseudo-Mercator) on GeoMap Suite?

Yes. You can test live coordinates and see practical examples using our companion Map Radius Tool tool.

QWhat are key concepts related to Web Mercator (EPSG:3857 / Pseudo-Mercator)?

Directly related terms include Universal Transverse Mercator, Tissot Indicatrix.