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EPSG:3395 — WGS 84 / World Mercator

WGS 84 / World Mercator — true ellipsoidal Mercator, used in global nautical charts.

Code
EPSG:3395
Type
Projected
Area
World - between 80°S and 84°N

PROJ definition

+proj=merc +lon_0=0 +k=1 +x_0=0 +y_0=0 +datum=WGS84 +units=m +no_defs +type=crs

Geographic bounds

W -180°   S -80°   E 180°   N 84°

Convert coordinates with EPSG:3395

About EPSG:3395

EPSG:3395 is the Mercator projection on the WGS 84 ellipsoid — the mathematically correct ellipsoidal Mercator, distinct from EPSG:3857's spherical 'Web Mercator'. The two differ by up to ~20 km at high latitudes, so the choice matters.

EPSG:3395 is the projection used by IHO ENC nautical charts and the IMO standard for maritime navigation. For terrestrial web mapping use EPSG:3857; for marine charts and any application that needs true conformal Mercator across the WGS 84 ellipsoid use EPSG:3395.

Common use cases

  • Nautical chart production (IHO S-57, S-100, S-101)
  • Maritime navigation systems
  • Global ocean datasets where ellipsoidal correctness matters

Common transformations from EPSG:3395

Frequently asked questions

EPSG:3395 vs EPSG:3857 — which should I pick?
EPSG:3395 is the true ellipsoidal Mercator (use for charts and analysis); EPSG:3857 is the spherical Web Mercator (use for tile maps).
What is the proj4 string for EPSG:3395?
The proj4 definition for EPSG:3395 is: +proj=merc +lon_0=0 +k=1 +x_0=0 +y_0=0 +datum=WGS84 +units=m +no_defs +type=crs
Where is EPSG:3395 used?
EPSG:3395 (WGS 84 / World Mercator) is defined for the area: World - between 80°S and 84°N.