Coordinates

Using this package it is possible to

1. Convert between the following coordinate systems:

   • World Geodetic System 1984 Lattitude, Longitude, EllipsoidalHeight (EPSG:3857, WGS84_LatLonH)
   • World Geodetic System 1984 Lattitude, Longitude (EPSG:4326, WGS84_LatLon)
   • World Geodetic System 1984 Longitude, Lattitude (CRS84, CRS84_LonLat)
   • World Geodetic System 1984 EartCentered-EarthFixed (EPSG:4978, WGS84_ECEF)
   • European Terrestrial Reference System 1989 Lattitude, Longitude, EllipsoidalHeight (EPSG:4937, ERTS89_LatLonH)
   • European Terrestrial Reference System 1989 Lattitude, Longitude (EPSG:4258, ERTS89_LatLon)
   • European Terrestrial Reference System 1989 EartCentered-EarthFixed (EPSG:4936, ERTS89_ECEF)](https://epsg.io/4936)
   • Rijksdriehoekscoördinaten (https://en.wikipedia.org/wiki/Amsterdam_Ordnance_Datum) (RD / EPSG:28992)
   • Rijksdriehoekscoördinaten + NAP height (RD / EPSG:7415)
   • WGS 84 / Pseudo-Mercator (EPSG:3857, WGS84_PseudoMercator)](https://epsg.io/3857)

2. convert between each of these coordinateSystems and Unity Vector3

Usage

Using coordinates

Creating a Coordinate from known values

Example, coordinate 10.02, 20.01, 1.05 in EPSG:4326, Coordinate Reference System.

$coordinate = new Coordinate(CoordinateSystem.WGS84LatLonHeight, 10.02, 20.01, 1.05);

alternatively when knowing Longitude = 10.02, Lattitude = 20.01 and height = 1.05, and you are not sure in what order they have to be:

$coordinate = new Coordinate(CoordinateSystem.WGS84LatLonHeight);
$coordinate.easting = longitudeValue
$coordinate.northing = lattitudeValue
$coordinate.height = heightValue

Testing the validity of a coordinate

you can test is a coordinate is valid using the function IsValid():

$bool isValid = CoordinateToTest.isValid();

returns true if: - the number of axis is correct AND - the AxisValues fall within the bounds of the valid area for the coordinatesystem

Converting to another CoordinateSystem

$rdCoordinate = originalCoordinate.Convert(CoordinateSystem.RDNAP);

find a CoordinateSystem by name

$bool CanHandleTheCoordainteSystem = CoordinateSytems.FindCoordinateSystem("coordinatesystemName", out NewCoordinateSystem)

each coordinateSystem has a unique name (in most case the epsg-code). the first found coordinateSystem who's name is contained in the searchterm will be returned. If a coordinateSystem is found, the function returns "True" If a coordinateSystem is not found, the function return "False" and the coordainteSystem is set to CoordinateSystem.Undefined

Connecting Coordinates to Unity

assigning a CoordinateSystem to Unity

$CoordinateSystems.connectedCoordinateSystem = CoordinateSystem.RDNAP;

assigning a location to the Unity Origin

$CoordinateSystems.SetOrigin(Coordinate that has to be at the Unity-Origin)

this coordinate does not have to be in the coordinateSystem that is assigned to Unity.

Creating a coordinate from an Unity Vector3

$newCoordinate = new Coordinate(UnityVector3)

Converting to a Vector3

$Vector3 = CoordinateToConvert.ToUnity()

Rotating geometry

When a geocentric coordinateSystem is attached to Unity, the geometry defined in this coordinatesystem has to be rotated so that the gravity-Updirection at the UnityOrigin aligns with UnityUp and the north-direction aligns with the Unity Z-axis.

different coordinatesystems use different Up- and East-directions. When coordinateSystem A is connected to Unity, but you have geometry (for example a mesh) that is defined in coordinateSystem B, a rotation might have to be applied to ensure that the geometry aligns nicely with the other objects in unity.

$Quaternion rotationInUnity = CoordinateAtOriginOfGeometry.RotationToLocalGravityUp()
$transform.rotation = rotationInUnity

• (for now) we assume that the mesh itself is defined in a left-handed, Y-up style. (even though most official coordinatesystems are righthanded and Z-up), most geometry-parsers in unity already change this definition

Backwards compatibility

In Netherlands3D, we used to make use of conversion methods on the CoordinateConverter -such as RDtoWGS84- and Vector3 classes per Coordinate System. This architecture is not scalable to support the plethora of CRS out there, and as such these are all deprecated and replaced by Coordinate.Convert(targetCRS)