GeoreferenceSystem

Georeference System

The Georeference System handles conversions between Unity coordinates and geospatial coordinates.

public class GeoreferenceSystem 
  : MonoBehaviour

Includes

• GlmSharp
• OpenDis.Dis1998
• System
• UnityEngine

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Members

Access		Type	Name	Description
	const	double	EARTH_FLATTENING	The WGS-84 inverse flattening value of the Earth.
	const	double	EARTH_MAJOR_AXIS	The WGS-84 equatorial radius of the Earth in meters.
	const	double	EARTH_MINOR_AXIS	The WGS-84 polar radius of the Earth in meters.
Public		EEarthShape	EarthShape	The shape of the world in the scene.
Private		dmat4	ECEFFrameToWorldFrame	The matrix to transform a vector from ECEF CRS to Unity.
	const	double	EPSILON	Machine Epsilon - float approx 1e-7, double approx 2e-16
Private		Vector3Double	GeographicEllipsoid	Vector containing ellipsoidal information pertaining to the WGS-84 Earth (X = EARTH_MAJOR_AXIS, Y = EARTH_MAJOR_AXIS, Z = EARTH_MINOR_AXIS).
Private		Vector3Double	OriginECEF	The ECEF location of the Unity origin.
Public		FLatLonAlt	OriginLLA	The Latitude in decimal degrees, Longitude in decimal degrees, and Altitude in meters of the Unity origin (0, 0, 0).
Private		dmat4	UnityFrameToWorldFrame	The matrix to transform a vector into the Unity coordinate frame.
Private		dmat4	WorldFrameToECEFFrame	The matrix to transform a vector from Unity to ECEF CRS.
Private		dmat4	WorldFrameToUnityFrame	The matrix to transform a vector from the Unity coordinate frame.

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Functions

Access		Return	Name	Description
Private		void	Awake()	Awake is called when the script instance is being loaded.
Private		Vector3Double	ecef_to_flatearth(Vector3Double ecefLocation)	Transforms the given ECEF XYZ location to a flat Earth coordinate.
Public		Vector3	ECEFToUnity(Vector3Double ECEFLocation, Vector3 OriginRebasingOffset)	Converts ECEF coordinates to Unity coordinates.
Private		Vector3Double	flatearth_to_ecef(Vector3Double FlatEarthCoords)	Transforms the given flat Earth coordinates to an ECEF XYZ coordinate
Private		FLatLonAlt	flatearth_to_geodetic(Vector3Double FlatEarthCoords)	Transforms the given flat Earth coordinates to geodetic Lat, Lon, Alt coordinates
Private		Vector3Double	geodetic_to_flatearth(FLatLonAlt latlonalt)	Transforms the given geodetic Lat, Lon, Alt coordinate to a flat earth coordinate
Public		FEastNorthUp	GetENUVectorsAtECEFLocation(Vector3Double ECEFLocation)	Get the East, North, Up vectors at the given ECEF location.
Public		FEastNorthUp	GetENUVectorsAtEngineLocation(Vector3 UnityLocation, Vector3 OriginRebasingOffset)	Get the East, North, Up vectors at the given Unity location.
Public		FNorthEastDown	GetNEDVectorsAtECEFLocation(Vector3Double ECEFLocation)	Get the North, East, Down vectors at the given ECEF location.
Public		FNorthEastDown	GetNEDVectorsAtEngineLocation(Vector3 UnityLocation, Vector3 OriginRebasingOffset)	Get the North, East, Down vectors at the given Unity location.
Public		Vector3Double	GetOriginECEF()	Gets the ECEF location of the Unity origin.
Public		FLatLonAlt	GetOriginLLA()	Gets the Lat, Lon, Alt coordinates of the Unity origin.
Private		string	GetUTMLetterDesignator(double Lat)	Gets the UTM letter designator for the given latitude.
Private		dmat4	GetWorldFrameToECEFFrame(Vector3Double Ellisoid, Vector3Double ECEFLocation)	Get the matrix to transform a vector from Unity to ECEF CRS.
Public		FUTMCoordinates	LatLonAltToProjected(FLatLonAlt LatLonAltToConvert)	Converts the given Lat and Lon to UTM coordinates. Lat and Lon should be in decimal degrees.
Public		Vector3	LatLonAltToUnity(FLatLonAlt LatLonAlt, Vector3 OriginRebasingOffset)	Converts the given Lat, Lon, Alt coordinates to Unity coordinates.
Private		void	SetupVars()	Initializes the needed variables that are used for geospatial conversions.
Public		Vector3Double	UnityToECEF(Vector3 UnityLocation, Vector3 OriginRebasingOffset)	Converts Unity coordinates into ECEF coordinates.
Public		FLatLonAlt	UnityToLatLonAlt(Vector3 UnityLocation, Vector3 OriginRebasingOffset)	Converts Unity coordinates into geodetic Lat, Lon, Alt coordinates.

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Details

EARTH_FLATTENING

const double EARTH_FLATTENING = 298.257223563

The WGS-84 inverse flattening value of the Earth.

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EARTH_MAJOR_AXIS

const double EARTH_MAJOR_AXIS = 6378137

The WGS-84 equatorial radius of the Earth in meters.

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EARTH_MINOR_AXIS

const double EARTH_MINOR_AXIS = 6356752.314245

The WGS-84 polar radius of the Earth in meters.

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EarthShape

public EEarthShape EarthShape

The shape of the world in the scene.

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ECEFFrameToWorldFrame

private dmat4 ECEFFrameToWorldFrame

The matrix to transform a vector from ECEF CRS to Unity.

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EPSILON

const double EPSILON = 2.220446049250313e-16

Machine Epsilon - float approx 1e-7, double approx 2e-16

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GeographicEllipsoid

private Vector3Double GeographicEllipsoid = new Vector3Double
{
    X = EARTH_MAJOR_AXIS,
    Y = EARTH_MAJOR_AXIS,
    Z = EARTH_MINOR_AXIS
}

Vector containing ellipsoidal information pertaining to the WGS-84 Earth.

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OriginECEF

private Vector3Double OriginECEF

The ECEF location of the Unity origin.

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OriginLLA

public FLatLonAlt OriginLLA

The Latitude in decimal degrees, Longitude in decimal degrees, and Altitude in meters of the Unity origin (0, 0, 0).

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UnityFrameToWorldFrame

private dmat4 UnityFrameToWorldFrame

The matrix to transform a vector into the Unity coordinate frame.

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WorldFrameToECEFFrame

private dmat4 WorldFrameToECEFFrame

The matrix to transform a vector from Unity to ECEF CRS.

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WorldFrameToUnityFrame

private dmat4 WorldFrameToUnityFrame

The matrix to transform a vector from the Unity coordinate frame.

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Awake

private void Awake()

Awake is called when the script instance is being loaded.

https://docs.unity3d.com/ScriptReference/MonoBehaviour.Awake.html

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ecef_to_flatearth

private Vector3Double ecef_to_flatearth
(
    Vector3Double ecefLocation
)

Transforms the given ECEF XYZ location to a flat Earth coordinate.

Parameter	Description
ecefLocation	The ECEF location to transform.

Returns
The X (East), Y (North), and Z (Up) location in a flat Earth coordinate system.

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ECEFToUnity

public Vector3 ECEFToUnity
(
    Vector3Double ECEFLocation,
    Vector3 OriginRebasingOffset = default
)

Converts ECEF coordinates to Unity coordinates.

Parameter	Description
ECEFLocation	The ECEF location to transform.
OriginRebasingOffset	The offset that has been applied to the origin if any origin shifting has been performed.

Returns
The Unity coordinates.

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flatearth_to_ecef

private Vector3Double flatearth_to_ecef
(
    Vector3Double FlatEarthCoords
)

Transforms the given flat Earth coordinates to an ECEF XYZ coordinate

Parameter	Description
FlatEarthCoords	The flat Earth X (East), Y (North), and Z (Up) coordinate to transform.

Returns
The ECEF XYZ location.

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flatearth_to_geodetic

private FLatLonAlt flatearth_to_geodetic
(
    Vector3Double FlatEarthCoords
)

Transforms the given flat Earth coordinates to geodetic Lat, Lon, Alt coordinates

Parameter	Description
FlatEarthCoords	The flat Earth X (East), Y (North), and Z (Up) coordinate to transform.

Returns
The Lat in decimal degrees, Lon in decimal degrees, and Alt in meters.

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geodetic_to_flatearth

private Vector3Double geodetic_to_flatearth
(
    FLatLonAlt latlonalt
)

Transforms the given geodetic Lat, Lon, Alt coordinate to a flat earth coordinate

Parameter	Description
latlonalt	The Lat in decimal degrees, Lon in decimal degrees, and Alt in meters to transform.

Returns
The X (East), Y (North), and Z (Up) location in a flat Earth coordinate system.

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GetENUVectorsAtECEFLocation

public FEastNorthUp GetENUVectorsAtECEFLocation
(
    Vector3Double ECEFLocation
)

Get the East, North, Up vectors at the given ECEF location.

Parameter	Description
ECEFLocation	The ECEF location to get the East, North, Up vectors of.

Returns
The East, North, Up vectors in terms of Unity's coordinate system

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GetENUVectorsAtEngineLocation

public FEastNorthUp GetENUVectorsAtEngineLocation
(
    Vector3 UnityLocation,
    Vector3 OriginRebasingOffset = default
)

Get the East, North, Up vectors at the given Unity location.

Parameter	Description
UnityLocation	The Unity location to get the East, North, Up vectors of.
OriginRebasingOffset	The offset that has been applied to the origin if any origin shifting has been performed.

Returns
The East, North, Up vectors in terms of Unity's coordinate system.

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GetNEDVectorsAtECEFLocation

public FNorthEastDown GetNEDVectorsAtECEFLocation
(
    Vector3Double ECEFLocation
)

Get the North, East, Down vectors at the given ECEF location.

Parameter	Description
ECEFLocation	The ECEF location to get the North, East, Down vectors of.

Returns
The North, East, Down vectors in terms of Unity's coordinate system

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GetNEDVectorsAtEngineLocation

public FNorthEastDown GetNEDVectorsAtEngineLocation
(
    Vector3 UnityLocation,
    Vector3 OriginRebasingOffset = default
)

Get the North, East, Down vectors at the given Unity location.

Parameter	Description
UnityLocation	The Unity location to get the North, East, Down vectors of.
OriginRebasingOffset	The offset that has been applied to the origin if any origin shifting has been performed.

Returns
The North, East, Down vectors in terms of Unity's coordinate system.

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GetOriginECEF

public Vector3Double GetOriginECEF()

Gets the ECEF location of the Unity origin.

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GetOriginLLA

public FLatLonAlt GetOriginLLA()

Gets the Lat, Lon, Alt coordinates of the Unity origin.

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GetUTMLetterDesignator

private string GetUTMLetterDesignator
(
    double Lat
)

Gets the UTM letter designator for the given latitude.

Parameter	Description
Lat	The latitude to get the UTM letter designator of. Should be given in decimal degrees.

Returns
A string containing the UTM letter designator.

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GetWorldFrameToECEFFrame

private dmat4 GetWorldFrameToECEFFrame
(
    Vector3Double Ellisoid,
    Vector3Double ECEFLocation
)

Get the matrix to transform a vector from Unity to ECEF CRS.

Parameter	Description
Ellisoid	The ellipsoid of the world.
ECEFLocation	The ECEF to get the world frame of.

Returns
The transformation matrix needed to convert Unity locations to ECEF CRS.

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LatLonAltToProjected

public FUTMCoordinates LatLonAltToProjected
(
    FLatLonAlt LatLonAltToConvert
)

Converts the given Lat and Lon to UTM coordinates. Lat and Lon should be in decimal degrees.

Parameter	Description
LatLonAltToConvert	The Lat and Lon to convert

Returns
The UTM Coordinates.

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LatLonAltToUnity

public Vector3 LatLonAltToUnity
(
    FLatLonAlt LatLonAlt,
    Vector3 OriginRebasingOffset = default
)

Converts the given Lat, Lon, Alt coordinates to Unity coordinates.

Parameter	Description
LatLonAlt	The Lat, Lon, Alt coordinates to transform.
OriginRebasingOffset	The offset that has been applied to the origin if any origin shifting has been performed.

Returns
The Unity coordinates.

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SetupVars

private void SetupVars()

Initializes the needed variables that are used for geospatial conversions.

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UnityToECEF

public Vector3Double UnityToECEF
(
    Vector3 UnityLocation,
    Vector3 OriginRebasingOffset = default
)

Converts Unity coordinates into ECEF coordinates.

Parameter	Description
UnityLocation	The Unity coordinates to transform.
OriginRebasingOffset	The offset that has been applied to the origin if any origin shifting has been performed.

Returns
The ECEF XYZ coordinates.

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UnityToLatLonAlt

public FLatLonAlt UnityToLatLonAlt
(
    Vector3 UnityLocation,
    Vector3 OriginRebasingOffset = default
)

Converts Unity coordinates into geodetic Lat, Lon, Alt coordinates.

Parameter	Description
UnityLocation	The Unity coordinates to transform.
OriginRebasingOffset	The offset that has been applied to the origin if any origin shifting has been performed.

Returns
The Lat, Lon, Alt coordinates.

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