Coord v0.1.0 Coord.Datum.Ellipsoid View Source

Specified the shape of the surface of a Coord.Datum. See the typedoc for Coord.Datum.Ellipsoid.t/0 for the specifics of how to create an instance.

Concept

An ellipsoid is a surface that approximates the shape of the earth. It is constructed by flattening a sphere. WGS84 is defined by an ellipsoid with specific parameters. Other datum either use different parameters of different shapes altogether.

Source: https://en.wikipedia.org/wiki/Reference_ellipsoid

Link to this section Summary

Types

t()

Assumes an oblate sphereoid datum surface like WGS84. Other types of surfaces are not currently supported.

Link to this section Types

Specs

t() :: %Coord.Datum.Ellipsoid{a: integer(), b: float(), f: float()}

Assumes an oblate sphereoid datum surface like WGS84. Other types of surfaces are not currently supported.

Keys:

  • :a: equatorial radius of the sphereoid in meters
  • :b: the polar semi-minor axis in meters (equals a * (1 − f))
  • :f: flattening (also known as ellipticity or oblateness)

For example, the function Coord.Datum.wgs84/0 creates an instance of an Coord.Datum.Ellipsoid that looks like this:

%Coord.Datum.Ellipsoid{a: 6_378_137, b: 6_356_752.314245, f: 1 / 298.257223563}