Learn ARCore - Fundamentals of Google ARCore

Mapping, GIS, and GPS

Unity, as we already learned, tracks its objects in 3D space using a point with a Cartesian coordinate reference system of x, y, and z. When we plot a point on a map of the world, it is no different; we need to reference the point, except that now we need to use a spherical or geographic reference system to represent a position on the earth, because as we all know, the earth is spherical. However, converting between a geographic system and Cartesian system is expensive. Many mapping applications, therefore, use an intermediary reference known as earth-centered, earth-fixed (ECEF), which represents mapping data on an earth-fixed Cartesian coordinate reference system. The following is a diagram shows the differences between ...