Class: LatLon_NvectorEllipsoidal

latlon-nvector-ellipsoidal~LatLon_NvectorEllipsoidal

Latitude/longitude points on an ellipsoidal model earth augmented with methods for calculating delta vectors between points, and converting to n-vectors.

Constructor

new LatLon_NvectorEllipsoidal(lat, lon, heightopt, datumopt)

Creates a LatLon point on an ellipsoidal model earth.
Parameters:
Name Type Attributes Default Description
lat number Latitude in degrees.
lon number Longitude in degrees.
height number <optional>
 0 Height above ellipsoid in metres.
datum LatLon.datums <optional>
 WGS84 Datum this point is defined within.
Source:

Methods

deltaTo(point) → {Ned}

Calculates delta from ‘this’ point to supplied point. The delta is given as a north-east-down NED vector. Note that this is a linear delta, unrelated to a geodesic on the ellipsoid. Points need not be defined on the same datum.
Parameters:
Name Type Description
point LatLon Point delta is to be determined to.
Source:
Returns:
Delta from ‘this’ point to supplied point in local tangent plane of this point.
Type
Ned
Example
var a = new LatLon(49.66618, 3.45063);
  var b = new LatLon(48.88667, 2.37472);
  var delta = a.deltaTo(b);   // [N:-86126,E:-78900,D:1069]
  var dist = delta.length;    // 116807.681 m
  var brng = delta.bearing;   // 222.493°
  var elev = delta.elevation; //  -0.5245°

destinationPoint(delta) → {LatLon}

Calculates destination point using supplied delta from ‘this’ point.
Parameters:
Name Type Description
delta Ned Delta from ‘this’ point to supplied point in local tangent plane of this point.
Source:
Returns:
Destination point.
Type
LatLon
Example
var a = new LatLon(49.66618, 3.45063);
  var delta = Ned.fromDistanceBearingElevation(116807.681, 222.493, -0.5245); // [N:-86126,E:-78900,D:1069]
  var b = a.destinationPoint(delta);                                          // 48.88667°N, 002.37472°E

(private) equals(point) → {bool}

Checks if another point is equal to ‘this’ point.
Parameters:
Name Type Description
point LatLon Point to be compared against this point.
Source:
Returns:
True if points are identical.
Type
bool
Example
var p1 = new LatLon(52.205, 0.119);
  var p2 = new LatLon(52.205, 0.119);
  var equal = p1.equals(p2); // true

toCartesian() → {Cartesian}

Converts ‘this’ point from (geodetic) latitude/longitude coordinates to (geocentric) cartesian (x/y/z) coordinates.
Source:
Returns:
Cartesian point equivalent to lat/lon point, with x, y, z in metres from earth centre. TODO this simply replicates LatLon.toCartesian() from latlon-ellipsoidal.js but returns Cartesian_Nvector in place of Cartesian, so that toNvector() is available; there must be a better way of doing this!
Type
Cartesian

toNvector() → {Nvector}

Converts ‘this’ lat/lon point to n-vector (normal to earth's surface).
Source:
Returns:
N-vector representing lat/lon point.
Type
Nvector
Example
var p = new LatLon(45, 45);
  var n = p.toNvector(); // [0.5000, 0.5000, 0.7071]