HEIF (.heic), JPEG などに含まれる EXIF 情報などから緯度経度・時刻・姿勢(Unity準拠)を読み込む C# サンプル。 https://twitter.com/ksasao/status/1426522324623265800

PhotoData.cs

using MetadataExtractor;
using MetadataExtractor.Formats.Exif;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Numerics;
using System.Text;
using System.Text.RegularExpressions;
using System.Threading.Tasks;

namespace metadata
{
    // NuGet で MetadataExtractor を追加してください 
    public class PhotoData
    {
        /// <summary>
        /// 撮影日時
        /// </summary>
        public DateTime Date { get; set; } = new DateTime(0);
        /// <summary>
        /// タイムゾーン
        /// </summary>
        public string TimeZone { get; set; } = "";
        /// <summary>
        /// 緯度(Google Maps準拠)
        /// </summary>
        public double Latitude { get; set; } = Double.MinValue;
        /// <summary>
        /// 経度(Google Maps準拠)
        /// </summary>
        public double Longitude { get; set; } = Double.MinValue;
        /// <summary>
        /// 高度(m)
        /// </summary>
        public double Altitude { get; set; } = Double.MinValue;
        /// <summary>
        /// 北を0, 東を90 とする方位角(°)
        /// </summary>
        public double Azimuth { get; set; } = Double.MinValue;
        /// <summary>
        /// Unity のカメラの Rotation(カメラの向きに合わせて補正済み)。
        /// Yは常に0。必要に応じて Azimuth を利用する。
        /// </summary>
        public Vector3 Rotation { get; set; } = new Vector3 { X = float.MinValue, Y = float.MinValue, Z = float.MinValue };

        private string[] dateTimeFormats = { "yyyy:MM:dd HH:mm:ss.fff", "yyyy:MM:dd HH:mm:ss" };

        /// <summary>
        /// 値が設定されているか
        /// </summary>
        /// <param name="obj">PhotoDataクラスのプロパティ</param>
        /// <returns>値が設定されていれば true</returns>
        public static bool HasValue(Object obj)
        {
            Type type = obj.GetType();
            if (type == typeof(DateTime))
            {
                return ((DateTime)obj) != new DateTime(0);
            } else if (type == typeof(string))
            {
                return !string.IsNullOrEmpty((string)obj);
            } else if(type == typeof(double))
            {
                return ((double)obj) != double.MinValue;
            }else if(type == typeof(Vector3))
            {
                return (((Vector3)obj).X != float.MinValue);
            }
            return false;
        }

        public PhotoData() { }
        public PhotoData(string filename)
        {
            IEnumerable<Directory> directories= ImageMetadataReader.ReadMetadata(filename);
            Parse(directories);
        }

        private void Parse(IEnumerable<Directory> directories)
        {
            // 日付・時刻
            var subIfdDirectory = directories.OfType<ExifSubIfdDirectory>().FirstOrDefault();
            var ifdo = directories.OfType<ExifIfd0Directory>().FirstOrDefault();
            var dateTime = subIfdDirectory?.GetDescription(ExifDirectoryBase.TagDateTimeOriginal);
            var timeZone = subIfdDirectory?.GetDescription(ExifDirectoryBase.TagTimeZoneOriginal);

            if(dateTime == null)
            {
                dateTime = ifdo?.GetDescription(ExifDirectoryBase.TagDateTimeOriginal);
            }
            // .mov / .mp4 の場合
            if(dateTime == null)
            {
                var str = GetString(directories, "QuickTime Movie Header", "Created");
                if (str != null)
                {
                    var utc = DateTime.ParseExact(str.Substring(str.IndexOf(" ")+1),
                        "M d HH:mm:ss yyyy",
                        System.Globalization.DateTimeFormatInfo.InvariantInfo,
                        System.Globalization.DateTimeStyles.None);
                    var local = TimeZoneInfo.ConvertTimeFromUtc(utc,TimeZoneInfo.Local);
                    var offset = local - utc;

                    dateTime = local.ToString("yyyy:MM:dd HH:mm:ss");
                    timeZone = $"{offset.Hours:+0,0;-0,0;+0,0}:{offset.Minutes:00}";
                }
            }
            if (dateTime != null)
            {
                Date = DateTime.ParseExact(dateTime,
                    dateTimeFormats,
                    System.Globalization.DateTimeFormatInfo.InvariantInfo,
                    System.Globalization.DateTimeStyles.None);
            }
            if(!string.IsNullOrEmpty(timeZone))
            {
                TimeZone = timeZone;
            }


            // 緯度・経度・高度・方位角
            var gps = directories.OfType<GpsDirectory>().FirstOrDefault();
            var latitude = gps?.GetDescription(GpsDirectory.TagLatitude);
            var longitude = gps?.GetDescription(GpsDirectory.TagLongitude);
            var altitudeRef = gps?.GetDescription(GpsDirectory.TagAltitudeRef);
            var altitude = gps?.GetDescription(GpsDirectory.TagAltitude);
            var direction = gps?.GetDescription(GpsDirectory.TagImgDirection);
            if (latitude != null && longitude != null)
            {
                Latitude = GetDecimal(latitude);   // 方位により符号が異なる
                Longitude = GetDecimal(longitude); // 方位により符号が異なる
            }
            if (altitudeRef != null && altitude != null)
            {
                Altitude = GetMetres(altitude) * (altitudeRef == "Sea level" ? 1.0 : -1.0);
            }
            if (direction != null)
            {
                Azimuth = GetAzimuth(direction);
            }
            // .mov / .mp4 の場合
            if (!HasValue(Latitude))
            {
                var str = GetString(directories, "QuickTime Metadata Header", "GPS Location");
                if (str != null)
                {
                    MatchCollection matches = Regex.Matches(str, @"[+-]?\d+(?:\.\d+)?");
                    if(matches.Count >= 2)
                    {
                        Latitude = Convert.ToDouble(matches[0].Value);
                        Longitude = Convert.ToDouble(matches[1].Value);
                    }
                    if(matches.Count == 3)
                    {
                        Altitude = Convert.ToDouble(matches[2].Value);
                    }
                }
            }


            // 加速度センサ
            var apple = directories.Where(x => x.Name == "Apple Makernote").FirstOrDefault();
            var acceleration = apple?.Tags.Where(x => x.Name == "Acceleration Vector").FirstOrDefault();
            var orientation = ifdo?.GetDescription(ExifDirectoryBase.TagOrientation);
            if (acceleration != null && orientation != null)
            {
                Rotation = GetVector3(acceleration.Description, orientation);
            }
        }

        private double GetDecimal(string deg)
        {
            double result = double.MinValue;
            int p0 = deg.IndexOf("°");
            int p1 = deg.IndexOf("\'");
            int p2 = deg.IndexOf("\"");
            if(p0 > 0 && p1 > p0 && p2 > p1)
            {
                double h = Convert.ToDouble(deg.Substring(0, p0).Trim());
                double m = Convert.ToDouble(deg.Substring(p0 + 1, p1 - p0 - 1).Trim()) / 60.0;
                double s = Convert.ToDouble(deg.Substring(p1 + 1, p2 - p1 - 1).Trim()) / 3600.0;
                if(h > 0)
                {
                    result = h + m + s;
                }
                else
                {
                    result = h - m - s;
                }
            }
            return result;
        }

        private string GetString(IEnumerable<Directory> directories, string directoryName, string tag)
        {
            var dir = directories.Where(x => x.Name == directoryName).FirstOrDefault();
            var str= dir?.Tags.Where(x => x.Name == tag).FirstOrDefault()?.Description;
            return str;
        }
        private double GetMetres(string alt)
        {
            double result = double.MinValue;
            int p = alt.IndexOf("metre");
            if (p > 0)
            {
                result = Convert.ToDouble(alt.Substring(0, p).Trim());
            }
            return result;
        }
        private double GetAzimuth(string dir)
        {
            double result = double.MinValue;
            int p = dir.IndexOf("degree");
            if(p > 0)
            {
                result = Convert.ToDouble(dir.Substring(0, p).Trim());
            }
            return result;
        }
        private Vector3 GetVector3(string acc, string orientation)
        {
            Vector3 a = new Vector3 { X = float.MinValue, Y = float.MinValue, Z = float.MinValue };
            string[] s = acc.Split(',');
            if (s.Length != 3)
            {
                return a;
            }
            for (int i = 0; i < 3; i++)
            {
                string[] t = s[i].Trim().Split(' ');
                float f = GetFloat(t[0]);
                switch (t[1].Trim())
                {
                    case "up":
                        a.X = -f;
                        break;
                    case "down":
                        a.X = f;
                        break;
                    case "left":
                        a.Y = -f;
                        break;
                    case "right":
                        a.Y = f;
                        break;
                    case "forward":
                        a.Z = -f;
                        break;
                    case "backward":
                        a.Z = f;
                        break;
                    default:
                        break;
                }
            }

            // Unity におけるカメラの Rotation に合わせる
            // 加速度センサでは方位はわからないため y は常に 0
            // y には必要に応じて Azimuth を利用する
            float x = 0f;
            float z = 0f;
            switch (orientation[0])
            {
                case 'T':
                    x = (float)(Math.Atan2(a.Z, a.Y) * 180.0 / Math.PI);
                    z = (float)(Math.Atan2(a.X, a.Y) * 180.0 / Math.PI);
                    break;
                case 'R':
                    x = (float)(Math.Atan2(a.Z, -a.X) * 180.0 / Math.PI);
                    z = (float)(Math.Atan2(a.Y, -a.X) * 180.0 / Math.PI);
                    break;
                case 'B':
                    x = (float)(Math.Atan2(a.Z, -a.Y) * 180.0 / Math.PI);
                    z = (float)(Math.Atan2(-a.X, -a.Y) * 180.0 / Math.PI);
                    break;
                case 'L':
                    x = (float)(Math.Atan2(a.Z, a.X) * 180.0 / Math.PI);
                    z = (float)(Math.Atan2(-a.Y, a.X) * 180.0 / Math.PI);
                    break;
                default:
                    break;
            }
            Vector3 result = new Vector3(x, 0, z);
            return result;
        }
        private float GetFloat(string str)
        {
            string s = str.Trim();
            return Convert.ToSingle(s.Substring(0, s.Length - 1));
        }
    }
}

Program.cs

using MetadataExtractor;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace metadata
{
    class Program
    {
        static void Main(string[] args)
        {
            string path = args[0];

            IEnumerable<Directory> directories = ImageMetadataReader.ReadMetadata(path);
            foreach (var directory in directories)
            {
                foreach (var tag in directory.Tags)
                {
                    Console.WriteLine($"{directory.Name} - {tag.Name} = {tag.Description}");
                }
            }
            Console.WriteLine();

            PhotoData photoData = new PhotoData(path);
            Console.Write("撮影日時  : ");
            if (PhotoData.HasValue(photoData.Date))
            {
                Console.WriteLine(photoData.Date.ToString("yyyy/MM/dd HH:mm:ss"));
            }
            else
            {
                Console.WriteLine("No data");
            }
            Console.Write("TimeZone  : ");
            if (PhotoData.HasValue(photoData.TimeZone))
            {
                Console.WriteLine(photoData.TimeZone);
            }
            else
            {
                Console.WriteLine("No data");
            }

            Console.Write("緯度・経度: ");
            if (PhotoData.HasValue(photoData.Latitude))
            {
                Console.WriteLine($"{photoData.Latitude},{photoData.Longitude}");
            }
            else
            {
                Console.WriteLine("No data");
            }

            Console.Write("高度(m)   : ");
            if (PhotoData.HasValue(photoData.Altitude))
            {
                Console.WriteLine(photoData.Altitude);
            }
            else
            {
                Console.WriteLine("No data");
            }

            Console.Write("方位角    : ");
            if (PhotoData.HasValue(photoData.Azimuth))
            {
                Console.WriteLine(photoData.Azimuth);
            }
            else
            {
                Console.WriteLine("No data");
            }

            Console.Write("Rotation  : ");
            if (PhotoData.HasValue(photoData.Rotation))
            {
                Console.WriteLine(photoData.Rotation);
            }
            else
            {
                Console.WriteLine("No data");
            }

            Console.ReadLine();
        }
    }
}