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.
Link to this section Summary
Link to this section Types
Specs
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}