Class: LatLonEllipsoidal_ReferenceFrame

latlon-ellipsoidal-referenceframe~LatLonEllipsoidal_ReferenceFrame(lat, lon, heightopt, referenceFrameopt, epochopt)

Latitude/longitude points on an ellipsoidal model earth, with ellipsoid parameters and methods for converting between reference frames and to geocentric (ECEF) cartesian coordinates.

Constructor

new LatLonEllipsoidal_ReferenceFrame(lat, lon, heightopt, referenceFrameopt, epochopt)

Creates geodetic latitude/longitude point on an ellipsoidal model earth using using a specified reference frame. Note that while the epoch defaults to the frame reference epoch, the accuracy of ITRF realisations is meaningless without knowing the observation epoch.
Parameters:
Name Type Attributes Default Description
lat number Geodetic latitude in degrees.
lon number Geodetic longitude in degrees.
height number <optional>
 0 Height above ellipsoid in metres.
referenceFrame LatLon.referenceFrames <optional>
 ITRF2014 Reference frame this point is defined within.
epoch number <optional>
 referenceFrame.epoch date of observation of coordinate (decimal year). defaults to reference epoch t₀ of reference frame.
Source:
Throws:
Unrecognised reference frame.
Type
TypeError
Example
import LatLon from '/js/geodesy/latlon-ellipsoidal-referenceframe.js';
  const p = new LatLon(51.47788, -0.00147, 0, LatLon.referenceFrames.ITRF2000);

Extends

  • LatLonEllipsoidal

Members

(static) ellipsoids

Ellipsoid parameters; semi-major axis (a), semi-minor axis (b), and flattening (f). The only ellipsoids used in modern geodesy are WGS-84 and GRS-80 (while based on differing defining parameters, the only effective difference is a 0.1mm variation in the minor axis b).
Source:
Example
const availableEllipsoids = Object.keys(LatLon.ellipsoids).join(); // WGS84,GRS80
  const a = LatLon.ellipsoids.Airy1830.a;                            // 6377563.396

(static) referenceFrames

Reference frames, with their base ellipsoids and reference epochs.
Source:
Example
const availableReferenceFrames = Object.keys(LatLon.referenceFrames).join(); // ITRF2014,ITRF2008, ...

(static) transformParameters

14-parameter Helmert transformation parameters between (dynamic) ITRS frames, and from ITRS frames to (static) regional TRFs NAD83, ETRF2000, and GDA94. This is a limited set of transformations; e.g. ITRF frames prior to ITRF2000 are not included. More transformations could be added on request. Many conversions are direct; for NAD83, successive ITRF transformations are chained back to ITRF2000.
Source:

epoch

Point’s observed epoch.
Source:

referenceFrame

Reference frame this point is defined within.
Source:

Methods

(static) parse(lat|latlon, lonopt, height, referenceFrame, epochopt) → {LatLon}

Parses a latitude/longitude point from a variety of formats. Latitude & longitude (in degrees) can be supplied as two separate parameters, as a single comma-separated lat/lon string, or as a single object with { lat, lon } or GeoJSON properties. The latitude/longitude values may be numeric or strings; they may be signed decimal or deg-min-sec (hexagesimal) suffixed by compass direction (NSEW); a variety of separators are accepted. Examples -3.62, '3 37 12W', '3°37′12″W'. Thousands/decimal separators must be comma/dot; use Dms.fromLocale to convert locale-specific thousands/decimal separators.
Parameters:
Name Type Attributes Default Description
lat|latlon number | string | Object Geodetic Latitude (in degrees) or comma-separated lat/lon or lat/lon object.
lon number <optional>
 Longitude in degrees.
height number Height above ellipsoid in metres.
referenceFrame LatLon.referenceFrames Reference frame this point is defined within.
epoch number <optional>
 referenceFrame.epoch date of observation of coordinate (decimal year).
Source:
Throws:
Unrecognised reference frame.
Type
TypeError
Returns:
Latitude/longitude point on ellipsoidal model earth using given reference frame.
Type
LatLon
Example
const p1 = LatLon.parse(51.47788, -0.00147, 17, LatLon.referenceFrames.ETRF2000);          // numeric pair
  const p2 = LatLon.parse('51°28′40″N, 000°00′05″W', 17, LatLon.referenceFrames.ETRF2000);   // dms string + height
  const p3 = LatLon.parse({ lat: 52.205, lon: 0.119 }, 17, LatLon.referenceFrames.ETRF2000); // { lat, lon } object numeric

convertReferenceFrame(toReferenceFrame) → {LatLon}

Converts ‘this’ lat/lon coordinate to new coordinate system.
Parameters:
Name Type Description
toReferenceFrame LatLon.referenceFrames Reference frame this coordinate is to be converted to.
Source:
Throws:
Undefined reference frame, Transformation not available.
Type
Error
Returns:
This point converted to new reference frame.
Type
LatLon
Example
const pEtrf = new LatLon(51.47788000, -0.00147000, 0, LatLon.referenceFrames.ITRF2000);
  const pItrf = pEtrf.convertReferenceFrame(LatLon.referenceFrames.ETRF2000); // 51.47787826°N, 000.00147125°W

toCartesian() → {Cartesian}

Converts ‘this’ point from (geodetic) latitude/longitude coordinates to (geocentric) cartesian (x/y/z) coordinates, based on same reference frame. Shadow of LatLonEllipsoidal.toCartesian(), returning Cartesian augmented with LatLonEllipsoidal_ReferenceFrame methods/properties.
Source:
Returns:
Cartesian point equivalent to lat/lon point, with x, y, z in metres from earth centre, augmented with reference frame conversion methods and properties.
Type
Cartesian

toString(formatopt, dpopt, dpHeightopt, referenceFrameopt) → {string}

Returns a string representation of ‘this’ point, formatted as degrees, degrees+minutes, or degrees+minutes+seconds.
Parameters:
Name Type Attributes Default Description
format string <optional>
 d Format point as 'd', 'dm', 'dms'.
dp number <optional>
 4|2|0 Number of decimal places to use: default 4 for d, 2 for dm, 0 for dms.
dpHeight number <optional>
 null Number of decimal places to use for height; default (null) is no height display.
referenceFrame boolean <optional>
 false Whether to show reference frame point is defined on.
Source:
Returns:
Comma-separated formatted latitude/longitude.
Type
string
Example
new LatLon(51.47788, -0.00147, 0, LatLon.referenceFrames.ITRF2014).toString();             // 51.4778°N, 000.0015°W
  new LatLon(51.47788, -0.00147, 0, LatLon.referenceFrames.ITRF2014).toString('dms');        // 51°28′40″N, 000°00′05″W
  new LatLon(51.47788, -0.00147, 42, LatLon.referenceFrames.ITRF2014).toString('dms', 0, 0); // 51°28′40″N, 000°00′05″W +42m