Contents
What does Web Mercator distort?
Answer. WGS 1984 Web Mercator and WGS 1984 Web Mercator (Auxiliary Sphere) use a conformal projection that preserves direction and the shape of data but distorts distance and area. Note that distances are very distorted in the east-west direction, north or south of the Equator.
What Epsg 3395?
EPSG:3857 (Pseudo Mercator) use globe with the same radius for the semi major and minor axis (see parameter a and b in proj4 EXTENSION tag), EPSG:3395 use a ellipsoid of rotation see inverse flatting value in SPHEROID tag.
Which is the most accurate Pseudo Mercator projection?
Spherical Pseudo-Mercator projection. Most of OSM, including the main tiling system, uses a Pseudo-Mercator projection where the Earth is modelized as if it was a perfect a sphere. This produces a fast approximation to the truer, but heavier elliptical projection, where the Earth would be projected on a more accurate ellipsoid (flattened on poles).
What’s the difference between Mercator and web Mercators?
It uses the same formulas as the standard Mercator as used for small-scale maps. However, the Web Mercator uses the spherical formulas at all scales whereas large-scale Mercator maps normally use the ellipsoidal form of the projection.
What is the official identifier for Mercator projection?
In 2008, EPSG provided the official identifier EPSG:3785 with the official name “Popular Visualisation CRS / Mercator”, but noted “It is not an official geodetic system”. This definition used a spherical (rather than ellipsoidal) model of the Earth.
Why is Mercator not used on OSM website?
FIXME: add spherical code in other languages here This projection gives more accurate aspect ratios for objects anywhere on Earth, and respects their angles with higher precision. However this project is not used on most maps used on the OSM websites and in editors. From a posting by Christopher Schmidt to the dev list on 2nd December 2006: