GPS Encoder by Michael Taylor Question [Solved]

Unity Engine
1

Hello,

I’ve been looking for a way to have game objects positioned dynamically on start. I would like to give GPS coordinates to the objects and have them set accordingly to XYZ positions in unity.

I found MIcahel Taylor’s GPSencoder script here GitHub - MichaelTaylor3D/UnityGPSConverter: Converts GPS coordinates to unity UCS coordinates and vice versa but can not figure out how to access it’s functions. The script has no public variables so I’m assuming that these need to be set through other scripts. However, I can’t figure out how to access the functions I want.

Here is the documentation:

It’s primarily

and

(which i assume that I can set by adding localOrigin = new Vector2 (90.0f, -46.0f) I’m interesting in using/accessing.

As usual, I feel like there is something obvious that I am missing, or are simply ignorant to. Does anyone have any suggestions on how I could go about this?

Thanks for your time,
Nathan

And, here’s the code:

//Copyright 2013 MichaelTaylor3D
//www.michaeltaylor3d.com

using UnityEngine;

public sealed class GPSEncoder : MonoBehaviour {

    /////////////////////////////////////////////////
    //////-------------Public API--------------//////
    /////////////////////////////////////////////////
 
    /// <summary>
    /// Convert UCS (X,Y,Z) coordinates to GPS (Lat, Lon) coordinates
    /// </summary>
    /// <returns>
    /// Returns Vector2 containing Latitude and Longitude
    /// </returns>
    /// <param name='position'>
    /// (X,Y,Z) Position Parameter
    /// </param>
    public static Vector2 USCToGPS(Vector3 position)
    {
        return GetInstance().ConvertUCStoGPS(position);
    }
 
    /// <summary>
    /// Convert GPS (Lat, Lon) coordinates to UCS (X,Y,Z) coordinates
    /// </summary>
    /// <returns>
    /// Returns a Vector3 containing (X, Y, Z)
    /// </returns>
    /// <param name='gps'>
    /// (Lat, Lon) as Vector2
    /// </param>
    public static Vector3 GPSToUCS(Vector2 gps)
    {
        return GetInstance().ConvertGPStoUCS(gps);
    }
 
    /// <summary>
    /// Convert GPS (Lat, Lon) coordinates to UCS (X,Y,Z) coordinates
    /// </summary>
    /// <returns>
    /// Returns a Vector3 containing (X, Y, Z)
    /// </returns>
    public static Vector3 GPSToUCS(float latitude, float longitude)
    {
        return GetInstance().ConvertGPStoUCS(new Vector2(latitude,longitude));
    }
 
    /// <summary>
    /// Change the relative GPS offset (Lat, Lon), Default (0,0),
    /// used to bring a local area to (0,0,0) in UCS coordinate system
    /// </summary>
    /// <param name='localOrigin'>
    /// Referance point.
    /// </param>
    public static void SetLocalOrigin(Vector2 localOrigin)
    {
        GetInstance()._localOrigin = localOrigin;
    }
     
    /////////////////////////////////////////////////
    //////---------Instance Members------------//////
    /////////////////////////////////////////////////
 
    #region Singleton
    private static GPSEncoder _singleton;
 
    private GPSEncoder()
    {
     
    }
 
    private static GPSEncoder GetInstance()
    {
        if(_singleton == null)
        {
            _singleton = new GPSEncoder();
        }
        return _singleton;
    }
    #endregion
 
    #region Instance Variables
    private Vector2 _localOrigin = Vector2.zero;
    private float _LatOrigin { get{ return _localOrigin.x; }} 
    private float _LonOrigin { get{ return _localOrigin.y; }}

    private float metersPerLat;
    private float metersPerLon;
    #endregion
 
    #region Instance Functions
    private void FindMetersPerLat(float lat) // Compute lengths of degrees
    {
        // Set up "Constants"
        float m1 = 111132.92f;    // latitude calculation term 1
        float m2 = -559.82f;        // latitude calculation term 2
        float m3 = 1.175f;      // latitude calculation term 3
        float m4 = -0.0023f;        // latitude calculation term 4
        float p1 = 111412.84f;    // longitude calculation term 1
        float p2 = -93.5f;      // longitude calculation term 2
        float p3 = 0.118f;      // longitude calculation term 3
     
        lat = lat * Mathf.Deg2Rad;
 
        // Calculate the length of a degree of latitude and longitude in meters
        metersPerLat = m1 + (m2 * Mathf.Cos(2 * (float)lat)) + (m3 * Mathf.Cos(4 * (float)lat)) + (m4 * Mathf.Cos(6 * (float)lat));
        metersPerLon = (p1 * Mathf.Cos((float)lat)) + (p2 * Mathf.Cos(3 * (float)lat)) + (p3 * Mathf.Cos(5 * (float)lat));    
    }

    private Vector3 ConvertGPStoUCS(Vector2 gps)
    {
        FindMetersPerLat(_LatOrigin);
        float zPosition  = metersPerLat * (gps.x - _LatOrigin); //Calc current lat
        float xPosition  = metersPerLon * (gps.y - _LonOrigin); //Calc current lat
        return new Vector3((float)xPosition, 0, (float)zPosition);
    }
 
    private Vector2 ConvertUCStoGPS(Vector3 position)
    {
        FindMetersPerLat(_LatOrigin);
        Vector2 geoLocation = new Vector2(0,0);
        geoLocation.x = (_LatOrigin + (position.z)/metersPerLat); //Calc current lat
        geoLocation.y = (_LonOrigin + (position.x)/metersPerLon); //Calc current lon
        return geoLocation;
    }
    #endregion
}
2 
GPSEncoder.USCToGPS(yourVectorHere);

I don’t think I’m missing anything…

1 Like
3

Thanks @Scabbage , I thought it had to be something simple.

It was this line that was causing me the problem:

if(_singleton.Equals(null))

I needed to change it to

 if (_singleton == null)

Also, if anyone is interested, its coding is slightly different than i’m used to so referencing it was a little different. but this works:

 private void Start()
    {
        local = new Vector2(_lat, _long);
        GPSEncoder.SetLocalOrigin(local);
    }

    public void Update()
    {
        Vector3 unityLocal = new Vector3(gameObject.transform.position.x, gameObject.transform.position.y, gameObject.transform.position.z);

        local = GPSEncoder.USCToGPS(unityLocal);

}